Fix where the documentation says "photos", but the example shows "posts" or "comments" by switching both to simply "posts"

Add further documentation + examples for the get, post, put and delete methods in ActionDispatch::Routing::Mapper::HttpHelpers

Sometimes it's easier to define routes inside Engine or
Application class definition (e.g. one file applications). The
problem with such case is that if there is a plugin that
has config/routes.rb file, it will trigger routes reload on application.
Since routes definition for application is not in config/routes.rb
file routes_reloader will fail to reload application's routes
properly. With this commit you can pass routes definition as a block
to routes method, which will allow to properly reload it:

class MyApp::Application < Rails::Application
  routes do
    resources :users
  end
end

Without that commit script_name always become '/', which
results in paths like //posts/1 instead of /posts/1

Avoid (@_var ||= nil) pattern by using initialize methods and ensuring everyone calls super as expected.

Signed-off-by: NSantiago Pastorino <santiago@wyeworks.com>

Signed-off-by: NSantiago Pastorino <santiago@wyeworks.com>

Signed-off-by: NSantiago Pastorino <santiago@wyeworks.com>

Raise ArgumentError instead of normalizing controller name when there is a leading slash [#5651 state:resolved]