Configures tests to minimize flackyness

Reference: https://bibwild.wordpress.com/2016/02/18/struggling-towards-reliable-capybara-javascript-testing/

The only thing I did not do was removing the random order in the tests.

spec/rails_helper.rb

@@ -19,6 +19,9 @@ ActiveRecord::Migration.maintain_test_schema!
 
 RSpec.configure do |config|
   config.infer_spec_type_from_file_location!
+  config.after :each do
+    Warden.test_reset!
+  end
 end
 
 Capybara.javascript_driver = :poltergeist