DEV: Rails 5.2 upgrade and global gem upgrade

This updates tests to use latest rails 5 practice
and updates ALL dependencies that could be updated

Performance testing shows that performance has not regressed
if anything it is marginally faster now.

Gemfile

@@ -13,13 +13,13 @@ if rails_master?
   gem 'rails', git: 'https://github.com/rails/rails.git'
   gem 'seed-fu', git: 'https://github.com/SamSaffron/seed-fu.git', branch: 'discourse'
 else
-  gem 'actionmailer', '~> 5.1'
-  gem 'actionpack', '~> 5.1'
-  gem 'actionview', '~> 5.1'
-  gem 'activemodel', '~> 5.1'
-  gem 'activerecord', '~> 5.1'
-  gem 'activesupport', '~> 5.1'
-  gem 'railties', '~> 5.1'
+  gem 'actionmailer', '~> 5.2'
+  gem 'actionpack', '~> 5.2'
+  gem 'actionview', '~> 5.2'
+  gem 'activemodel', '~> 5.2'
+  gem 'activerecord', '~> 5.2'
+  gem 'activesupport', '~> 5.2'
+  gem 'railties', '~> 5.2'
   gem 'sprockets-rails'
   gem 'seed-fu'
 end