Set up the groundwork for a port to Diesel

This PR changes the `users#show` endpoint to use Diesel instead of
rust-postgres, (and adds a test for that endpoint). I chose that
endpoint as it seemed likely to touch as few things as possible, but
enough to require setting up Diesel connection pooling, and testing.

I have also ported over the migrations to use Diesel's migration
infrastructure. The migration files (except the final migration) were
generated programatically. Any non-reversible migrations were not dumped
as these contained procedural data updates which aren't relevant to
setting up a new database.

`cargo run --bin migrate` will move all the entries in the old
migrations table into the one used by Diesel. That function is brittle
since it relies on Diesel internals. However, it really only matters for
existing contributors (and one deploy to Heroku), so when that function
breaks we can just delete it.

I've added an additional migration to make the schema compatible with
`infer_schema!`, which doesn't support tables that have no primary key.
I'm not using `infer_schema!` just yet, as it doesn't work with non-core
types and there are some tsvector columns.

I re-ordered the columns on the `User` struct, as diesel emits an
explicit select clause and then fetches columns by index rather than by
name. This means that the order has to match how it was defined to
Diesel (which in the case of `infer_schema!` will be the database
definition order). If we don't want this restriction, we can replace the
`infer_schema!` call with manual `table!` calls (which can be
automatically generated by `diesel print-schema`), and have the columns
ordered there to match the struct.

Differences to note
-------------------

The rust-postgres connection is set to require TLS when the env var
`HEROKU` is set. In Diesel, this would be to add `?sslmode=require` onto
the database URL. I'm unsure if heroku-postgres URLs already have this
or not, so I have not added any explicit code for that. It's a question
that should be answered before this is deployed.

Additionally, I chose not to automatically wrap each request in a
transaction. It's unneccessary most of the time, and seems like it was
only done to make testing easier. Since Diesel has explicit support for
"run tests in a transaction that never commits", we don't need that
here.

Author: sgrif

Cargo.lock

@@ -36,6 +36,9 @@ rustc-serialize = "0.3"
 license-exprs = "^1.3"
 dotenv = "0.8.0"
 toml = "0.2"
+diesel = { version = "0.11.0", features = ["postgres"] }
+diesel_codegen = { version = "0.11.0", features = ["postgres"] }
+r2d2-diesel = "0.11.0"
 
 conduit = "0.8"
 conduit-conditional-get = "0.8"

Cargo.toml

@@ -0,0 +1 @@
+DROP TABLE users;

migrations/20140924113530_dumped_migration_1/down.sql

@@ -0,0 +1,6 @@
+CREATE TABLE users (
+            id              SERIAL PRIMARY KEY,
+            email           VARCHAR NOT NULL UNIQUE,
+            gh_access_token VARCHAR NOT NULL,
+            api_token       VARCHAR NOT NULL
+        );

migrations/20140924113530_dumped_migration_1/up.sql

@@ -0,0 +1 @@
+DROP TABLE packages;

migrations/20140924114003_dumped_migration_2/down.sql

@@ -0,0 +1,5 @@
+CREATE TABLE packages (
+            id              SERIAL PRIMARY KEY,
+            name            VARCHAR NOT NULL UNIQUE,
+            user_id         INTEGER NOT NULL
+        );

migrations/20140924114003_dumped_migration_2/up.sql

@@ -0,0 +1 @@
+DROP TABLE versions;

migrations/20140924114059_dumped_migration_3/down.sql

@@ -0,0 +1,5 @@
+CREATE TABLE versions (
+            id              SERIAL PRIMARY KEY,
+            package_id      INTEGER NOT NULL,
+            num             VARCHAR NOT NULL
+        );

migrations/20140924114059_dumped_migration_3/up.sql

@@ -0,0 +1 @@
+ALTER TABLE versions DROP CONSTRAINT unique_num;

migrations/20140924115329_dumped_migration_4/down.sql

@@ -0,0 +1 @@
+ALTER TABLE versions ADD CONSTRAINT unique_num UNIQUE (package_id, num);

migrations/20140924115329_dumped_migration_4/up.sql

@@ -0,0 +1 @@
+DROP TABLE version_dependencies;

migrations/20140924120803_dumped_migration_5/down.sql

@@ -0,0 +1,4 @@
+CREATE TABLE version_dependencies (
+            version_id      INTEGER NOT NULL,
+            depends_on_id   INTEGER NOT NULL
+        );

migrations/20140924120803_dumped_migration_5/up.sql

@@ -0,0 +1 @@
+ALTER TABLE packages DROP COLUMN updated_at;

migrations/20140925132248_dumped_migration_6/down.sql

@@ -0,0 +1 @@
+ALTER TABLE packages ADD COLUMN updated_at TIMESTAMP NOT NULL DEFAULT now();

migrations/20140925132248_dumped_migration_6/up.sql

@@ -0,0 +1 @@
+ALTER TABLE packages DROP COLUMN created_at;

migrations/20140925132249_dumped_migration_7/down.sql

@@ -0,0 +1 @@
+ALTER TABLE packages ADD COLUMN created_at TIMESTAMP NOT NULL DEFAULT now();

migrations/20140925132249_dumped_migration_7/up.sql

@@ -0,0 +1,2 @@
+UPDATE packages SET updated_at = now() WHERE updated_at IS NULL;
+UPDATE packages SET created_at = now() WHERE created_at IS NULL;

migrations/20140925132250_dumped_migration_8/down.sql

@@ -0,0 +1 @@
+ALTER TABLE versions DROP COLUMN updated_at;

migrations/20140925132250_dumped_migration_8/up.sql

@@ -0,0 +1 @@
+ALTER TABLE versions ADD COLUMN updated_at TIMESTAMP NOT NULL DEFAULT now();

migrations/20140925132251_dumped_migration_9/down.sql

@@ -0,0 +1 @@
+ALTER TABLE versions DROP COLUMN created_at;

migrations/20140925132251_dumped_migration_9/up.sql

@@ -0,0 +1 @@
+ALTER TABLE versions ADD COLUMN created_at TIMESTAMP NOT NULL DEFAULT now();

migrations/20140925132252_dumped_migration_10/down.sql

@@ -0,0 +1,2 @@
+UPDATE versions SET updated_at = now() WHERE updated_at IS NULL;
+UPDATE versions SET created_at = now() WHERE created_at IS NULL;

migrations/20140925132252_dumped_migration_10/up.sql

@@ -0,0 +1,4 @@
+ALTER TABLE versions ALTER COLUMN updated_at DROP DEFAULT;
+ALTER TABLE versions ALTER COLUMN created_at DROP DEFAULT;
+ALTER TABLE packages ALTER COLUMN updated_at DROP DEFAULT;
+ALTER TABLE packages ALTER COLUMN created_at DROP DEFAULT;

migrations/20140925132253_dumped_migration_11/down.sql

@@ -0,0 +1 @@
+DROP TABLE metadata;

migrations/20140925132253_dumped_migration_11/up.sql

@@ -0,0 +1,3 @@
+CREATE TABLE metadata (
+            total_downloads        BIGINT NOT NULL
+        );

migrations/20140925132254_dumped_migration_12/down.sql

@@ -0,0 +1 @@
+DELETE FROM metadata;

migrations/20140925132254_dumped_migration_12/up.sql

@@ -0,0 +1 @@
+INSERT INTO metadata (total_downloads) VALUES (0);

migrations/20140925153704_dumped_migration_13/down.sql

@@ -0,0 +1 @@
+ALTER TABLE packages DROP COLUMN downloads;

migrations/20140925153704_dumped_migration_13/up.sql

@@ -0,0 +1 @@
+ALTER TABLE packages ADD COLUMN downloads INTEGER NOT NULL DEFAULT 0;

migrations/20140925153705_dumped_migration_14/down.sql

@@ -0,0 +1 @@
+ALTER TABLE versions DROP COLUMN downloads;

migrations/20140925153705_dumped_migration_14/up.sql

@@ -0,0 +1 @@
+ALTER TABLE versions ADD COLUMN downloads INTEGER NOT NULL DEFAULT 0;

migrations/20140925161623_dumped_migration_15/down.sql

@@ -0,0 +1,2 @@
+ALTER TABLE versions ALTER COLUMN downloads DROP DEFAULT;
+ALTER TABLE packages ALTER COLUMN downloads DROP DEFAULT;

migrations/20140925161623_dumped_migration_15/up.sql

@@ -0,0 +1 @@
+ALTER TABLE packages DROP COLUMN max_version;

migrations/20140925161624_dumped_migration_16/down.sql

@@ -0,0 +1 @@
+ALTER TABLE packages ADD COLUMN max_version VARCHAR;

migrations/20140925161624_dumped_migration_16/up.sql

@@ -0,0 +1 @@
+ALTER TABLE versions ALTER COLUMN downloads DROP NOT NULL;

migrations/20140925161625_dumped_migration_17/down.sql

@@ -0,0 +1 @@
+ALTER TABLE versions ALTER COLUMN downloads SET NOT NULL;

migrations/20140925161625_dumped_migration_17/up.sql

@@ -0,0 +1,2 @@
+ALTER TABLE crates RENAME TO packages;
+ALTER TABLE versions RENAME COLUMN crate_id TO package_id;

migrations/20140926130044_dumped_migration_18/down.sql

@@ -0,0 +1,2 @@
+ALTER TABLE packages RENAME TO crates;
+ALTER TABLE versions RENAME COLUMN package_id TO crate_id;

migrations/20140926130044_dumped_migration_18/up.sql

@@ -0,0 +1 @@
+DROP INDEX index_crate_updated_at;

migrations/20140926130046_dumped_migration_19/down.sql

@@ -0,0 +1 @@
+CREATE INDEX index_crate_updated_at ON crates (updated_at);

migrations/20140926130046_dumped_migration_19/up.sql

@@ -0,0 +1 @@
+DROP INDEX index_crate_created_at;

migrations/20140926174020_dumped_migration_20/down.sql

@@ -0,0 +1 @@
+CREATE INDEX index_crate_created_at ON crates (created_at);

migrations/20140926174020_dumped_migration_20/up.sql

@@ -0,0 +1 @@
+DROP INDEX index_crate_downloads;

migrations/20140929103749_dumped_migration_21/down.sql

@@ -0,0 +1 @@
+CREATE INDEX index_crate_downloads ON crates (downloads);

migrations/20140929103749_dumped_migration_21/up.sql

@@ -0,0 +1 @@
+DROP INDEX index_version_crate_id;

migrations/20140929103750_dumped_migration_22/down.sql

@@ -0,0 +1 @@
+CREATE INDEX index_version_crate_id ON versions (crate_id);

migrations/20140929103750_dumped_migration_22/up.sql

@@ -0,0 +1 @@
+DROP INDEX index_version_num;

migrations/20140929103751_dumped_migration_23/down.sql

@@ -0,0 +1 @@
+CREATE INDEX index_version_num ON versions (num);

migrations/20140929103751_dumped_migration_23/up.sql

@@ -0,0 +1 @@
+DROP INDEX index_version_dependencies_version_id;

migrations/20140929103752_dumped_migration_24/down.sql

@@ -0,0 +1 @@
+CREATE INDEX index_version_dependencies_version_id ON version_dependencies (version_id);

migrations/20140929103752_dumped_migration_24/up.sql

@@ -0,0 +1 @@
+DROP INDEX index_version_dependencies_depends_on_id;

migrations/20140929103753_dumped_migration_25/down.sql

@@ -0,0 +1 @@
+CREATE INDEX index_version_dependencies_depends_on_id ON version_dependencies (depends_on_id);

migrations/20140929103753_dumped_migration_25/up.sql

@@ -0,0 +1 @@
+DROP TABLE crate_downloads;

migrations/20140929103754_dumped_migration_26/down.sql

@@ -0,0 +1,6 @@
+CREATE TABLE crate_downloads (
+            id              SERIAL PRIMARY KEY,
+            crate_id        INTEGER NOT NULL,
+            downloads       INTEGER NOT NULL,
+            date            TIMESTAMP NOT NULL
+        );

migrations/20140929103754_dumped_migration_26/up.sql

@@ -0,0 +1 @@
+DROP INDEX index_crate_downloads_crate_id;

migrations/20140929103755_dumped_migration_27/down.sql

@@ -0,0 +1 @@
+CREATE INDEX index_crate_downloads_crate_id ON crate_downloads (crate_id);

migrations/20140929103755_dumped_migration_27/up.sql

@@ -0,0 +1 @@
+DROP INDEX index_crate_downloads_date;

migrations/20140929103756_dumped_migration_28/down.sql

@@ -0,0 +1 @@
+CREATE INDEX index_crate_downloads_date ON crate_downloads (date(date));

migrations/20140929103756_dumped_migration_28/up.sql

@@ -0,0 +1 @@
+DROP TABLE version_downloads;