Currently before running unit tests we are getting auto-required before
rspec-rails is getting required. This is bad because we need to wait
until rspec-rails is loaded before injecting Shoulda::Matchers::* into
the current RSpec context, otherwise matchers that clash with
rspec-rails (such as `render_template` will get overridden).
This is happening when creating and booting the Rails application.
Bundler will auto-require any gems in the Gemfile. One of these gems is
ourselves (via the `gemspec` line). Since there aren't any dependencies
in the gemspec, there's no need for us to be in the Gemfile.
This means that we no longer have to explicit `include` Rails
ActionController template assertions in the tests for `render_template`
as they should get included automatically for us.