Introduce since, description and default tags (#324)

Author: delvedor

docs/modeling-guide.md

@@ -278,4 +278,67 @@ class FooContainer {
   baz: BazDefinition
   faz: FazDefinition
 }
+```
+
+### Additional information
+
+If needed, you can specify additional information on each type with the approariate JSDoc tag.
+Following you can find a list of the supported tags:
+
+#### `@since`
+
+Every API already has a `@since` tag, which describes when an API has been added.
+You can specify an additional `@since` tag for every property that has been added afterwards.
+If the tag is not defined, it's assumed that the property has been added with the API the first time
+
+```ts
+/**
+ * @since 7.10.0
+ */
+class FooRequest {
+  bar: string
+  /** @since 7.11.0 */
+  baz: string
+  faz: string
+}
+```
+
+#### description
+
+You can add a description for each property, in this case there is no need to use a JSDoc tag.
+
+```ts
+class Foo {
+  bar: string
+  /** You can baz! */
+  baz: string
+  faz: string
+}
+```
+
+#### `@server_default`
+
+The server side default value if the property is not specified.
+Default values can only be specified on optional properties.
+
+```ts
+class Foo {
+  bar: string
+  /** @server_default hello */
+  baz?: string
+  faz: string
+}
+```
+
+#### `@doc_url`
+
+The documentation url for the parameter.
+
+```ts
+class Foo {
+  bar: string
+  /** @doc_url http://localhost:9200 */
+  baz?: string
+  faz: string
+}
 ```