Addition to support clearing RequestStore for Controller Specs

[justin808]

In my conversion to using request_store, controller specs were depending on a before hook in the controllers to do the clear. I'd like to propose that I submit a PR that contains the following:

1. Spec Helper to include that calls RequestStore.clear!:

module RequestStoreSupport
  # Override process to call clear, since that is done if Rack is available
  def process(*)
    RequestStore.clear!
    super
  end
end

1. Update the README to suggest adding this line to spec_helper.rb or rails_helper.rb

  config.include RequestStoreSupport, type: :controller

This was modeled after the way Devise::TestHelpers is done.

If this sounds good, I'll create a PR. This solution seems to be working for me.

[steveklabnik]

I think this makes more sense as something like https://github.com/steveklabnik/request_store#no-rails--racktest than as code.

[justin808]

@steveklabnik Are you confident that your approach would work for controller specs? And does my approach not get used for request and feature specs?