Phoenix - no route found for GET /static/js/some.js

I am migrating my rails application to phoenix framework.

I added some javascript (say some.js) and css files to web/static/js and web/static/css dir.

<%= static_path(@conn, "/js/some.js") %> in the front page page/index.html.eexdidn't work. It raised the exception (dev env):

Phoenix.Router.NoRouteError at GET /static/js/some.js
no route found for GET /static/js/some.js (VisualTrader.Router)

If I copied some.js to priv/static/js dir, it worked. So what I missed? I thought the assets pipeline worked like the one in rails, which auto precompiled resources.

Below list my phoenix framework environments:

• Elixir version

  elixir -v
  
  Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false]
  
  Elixir 1.3.0-dev (187f4f8)
  

• Phoenix version

  defp deps do
     [{:phoenix, "~> 1.1.2"},
     ...