Update rails to 5.1.6.1

Gemfile

@@ -6,7 +6,7 @@ git_source(:github) do |repo_name|
 end
 
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
-gem 'rails', '~> 5.1.5'
+gem 'rails', '~> 5.1.6.1'
 # Use postgresql as the database for Active Record
 gem 'pg', '>= 0.18', '< 2.0'
 # Use Puma as the app server