Updated documentation

Author: justinmchase

README.md

@@ -26,14 +26,15 @@ $ npm install datastore-s3
 ```
 
 ## Usage
-A bucket must be created prior to using datastore-s3. Please see the AWS docs for information on how to configure the S3 instance. A bucket name is required to be set at the s3 instance level, see the below example.
+If the flag `createIfMissing` is not set or is false, then the bucket must be created prior to using datastore-s3. Please see the AWS docs for information on how to configure the S3 instance. A bucket name is required to be set at the s3 instance level, see the below example.
 
 ```js
 const S3 = require('aws-sdk').S3
 const s3Instance = new S3({ params: { Bucket: 'my-ipfs-bucket' } })
 const S3Store = require('datastore-s3')
 const store = new S3Store('.ipfs/datastore', {
   s3: s3Instance
+  createIfMissing: false
 })
 ```
 

src/index.js

@@ -15,7 +15,8 @@ const Deferred = require('pull-defer')
 const pull = require('pull-stream')
 
 /* :: export type S3DSInputOptions = {
-  s3: S3Instance
+  s3: S3Instance,
+  createIfMissing: ?boolean
 }
 
 declare type S3Instance = {
@@ -43,6 +44,7 @@ class S3Datastore {
   /* :: path: string */
   /* :: opts: S3DSInputOptions */
   /* :: bucket: string */
+  /* :: createIfMissing: boolean */
 
   constructor (path /* : string */, opts /* : S3DSInputOptions */) {
     this.path = path