Upgraded to Rails 5.1.1

Gemfile

@@ -1,15 +1,15 @@
 source 'https://rubygems.org'
 
-ruby '2.3.0'
+ruby '2.4.0'
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
-gem 'rails', '4.2.5'
+gem 'rails', '5.1.1'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3', :group => :development
 
 # Use Uglifier as compressor for JavaScript assets
-gem 'uglifier', '>= 1.3.0'
+gem 'uglifier'
 # Use CoffeeScript for .js.coffee assets and views
-gem 'coffee-rails', '~> 4.0.0'
+gem 'coffee-rails'
 # See https://github.com/sstephenson/execjs#readme for more supported runtimes
 # gem 'therubyracer',  platforms: :ruby
 
@@ -18,9 +18,9 @@ gem 'jquery-rails'
 # Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
 gem 'turbolinks'
 # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
-gem 'jbuilder', '~> 2.0'
+gem 'jbuilder'
 # bundle exec rake doc:rails generates the API under doc/api.
-gem 'sdoc', '~> 0.4.0', :group => :doc
+gem 'sdoc', :group => :doc
 
 # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
 gem 'spring', :group => :development