Merge pull request rails#44423 from jonathanhefner/guides-update-sess…

…ion_store-instructions

Update `session_store` configuration instructions [ci-skip]

guides/source/configuring.md

@@ -333,13 +333,22 @@ Configures Rails to serve static files from the public directory. This option de
 
 #### `config.session_store`
 
-Specifies what class to use to store the session. Possible values are `:cookie_store` which is the default, `:mem_cache_store`, and `:disabled`. The last one tells Rails not to deal with sessions. Defaults to a cookie store with application name as the session key. Custom session stores can also be specified:
+Specifies what class to use to store the session. Possible values are `:cookie_store`, `:mem_cache_store`, a custom store, or `:disabled`. `:disabled` tells Rails not to deal with sessions.
+
+This setting is configured via a regular method call, rather than a setter. This allows additional options to be passed:
 
 ```ruby
+config.session_store :cookie_store, key: "_your_app_session"
+```
+
+If a custom store is specified as a symbol, it will be resolved to the `ActionDispatch::Session` namespace:
+
+```ruby
+# use ActionDispatch::Session::MyCustomStore as the session store
 config.session_store :my_custom_store
 ```
 
-This custom store must be defined as `ActionDispatch::Session::MyCustomStore`.
+The default store is a cookie store with the application name as the session key.
 
 #### `config.ssl_options`
 
@@ -572,11 +581,11 @@ Sets cookies for the request.
 
 #### `ActionDispatch::Session::CookieStore`
 
-Is responsible for storing the session in cookies. An alternate middleware can be used for this by changing the `config.action_controller.session_store` to an alternate value. Additionally, options passed to this can be configured by using `config.action_controller.session_options`.
+Is responsible for storing the session in cookies. An alternate middleware can be used for this by changing [`config.session_store`](#config-session-store).
 
 #### `ActionDispatch::Flash`
 
-Sets up the `flash` keys. Only available if `config.action_controller.session_store` is set to a value.
+Sets up the `flash` keys. Only available if [`config.session_store`](#config-session-store) is set to a value.
 
 #### `Rack::MethodOverride`
 
@@ -1148,10 +1157,6 @@ the top level, or on individual controllers.
 
 ### Configuring Action Dispatch
 
-#### `config.action_dispatch.session_store`
-
-Sets the name of the store for session data. The default is `:cookie_store`; other valid options include `:active_record_store`, `:mem_cache_store` or the name of your own custom class.
-
 #### `config.action_dispatch.cookies_serializer`
 
 Specifies which serializer to use for cookies. For more information, see [Action Controller Cookies](action_controller_overview.html#cookies).

guides/source/rails_on_rack.md

@@ -305,7 +305,9 @@ Much of Action Controller's functionality is implemented as Middlewares. The fol
 
 **`ActionDispatch::Flash`**
 
-* Sets up the flash keys. Only available if `config.action_controller.session_store` is set to a value.
+* Sets up the flash keys. Only available if [`config.session_store`][] is set to a value.
+
+[`config.session_store`]: configuring.html#config-session-store
 
 **`ActionDispatch::ContentSecurityPolicy::Middleware`**