 
   ### :browser pipeline
 
-  TODO: Describe plugs in the browser pipeline.
+  The following plugs are in the browser pipeline:
+
+    * `:fetch_session` - calls the `Plug.Conn.fetch_session/2` that
+      effectively fetches the session and makes it available in the
+      connection
 
   ### :api pipeline
 
-  TODO: Describe plugs in the api pipeline.
+  Currently there are no plugs in the `:api` pipeline.
 
   ### Customizing pipelines
 

          config :phoenix, YourApp.Router,
            session: [store: :cookie, key: "_your_app_key"]

    * `:parsers` - sets up the request parsers. If parsers are disabled,
      parameters won't be explicitly fetched before matching a route and
      functionality dependent on parameters, like the `Plug.MethodOverride`,
      will be disabled too. Defaults to:

          [accept: ["*/*"],
           json_decoder: Poison,
           parsers: [:urlencoded, :multipart, :json]]

    * `:static` - sets up static assets serving. Defaults to:

          [at: "/",
           from: Mix.Project.config[:app]]

  ### Runtime

    * `:http` - the configuration for the http server. Defaults to:

          [port: 4000]

    * `:https` - the configuration for the https server. Defaults to:

          [port: 4040]

    * `:secret_key_base` - a secret key used as base to generate secrets
      to encode cookies, session and friends. Defaults to nil.

    * `:url` - configuration for generating URLs throughout the app. Defaults to:

          [host: "localhost"]

  ## Web server

  TODO: documentation.

  """

  alias Phoenix.Plugs

  A router is the heart of a Phoenix application. It has three
  main responsibilities:

    * It defines a plug pipeline responsible for handling
      upcoming requests and dispatch those requests to
      controllers and other plugs

    * It hosts configuration for the router and related
      entities (like plugs)

    * It provides a wrapper for starting and stopping the
      router in a specific web server

  We will explore those responsibilities next.

