In FooController, I put method #bar whose only purpose is to run some
logic in the background and return a status 204 .
So in order to return only the 204 status code, I put at the end of
`render :nothing => true, :status => 204`
But then when surfing to /foo/bar, I get an error about "missing
template bar.rhtml". Is this a bug?
(The solution eventually was `render :text => ''`, but it really seems
like a hack and that `render => :nothing` should have been the valid
 http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html - "204 No
Content: The server has fulfilled the request but does not need to
return an entity-body"