merge multiple nested associations

Gemfile

@@ -2,25 +2,47 @@ source 'https://rubygems.org'
 
 gemspec
 
-platforms :ruby do
-  # sqlite3 1.3.9 does not work with rubinius 2.2.5:
-  # https://github.com/sparklemotion/sqlite3-ruby/issues/122
-  gem 'sqlite3', '1.3.8'
+version = ENV["RAILS_VERSION"] || "4.2"
+
+if version == 'master'
+  gem 'rack', github: 'rack/rack'
+  git 'https://github.com/rails/rails.git' do
+    gem 'railties'
+    gem 'activesupport'
+    gem 'activemodel'
+    gem 'actionpack'
+    # Rails 5
+    gem 'actionview'
+  end
+  # Rails 5
+  gem 'rails-controller-testing', github: 'rails/rails-controller-testing'
+else
+  gem_version = "~> #{version}.0"
+  gem 'railties', gem_version
+  gem 'activesupport', gem_version
+  gem 'activemodel', gem_version
+  gem 'actionpack', gem_version
 end
 
-platforms :jruby do
-  gem 'activerecord-jdbcsqlite3-adapter'
+if RUBY_VERSION < '2'
+  gem 'mime-types', [ '>= 2.6.2', '< 3' ]
 end
 
-version = ENV["RAILS_VERSION"] || "4.0.2"
-rails = case version
-        when "master"
-          {:github => "rails/rails"}
-        else
-          "~> #{version}"
-        end
-gem "rails", rails
+# https://github.com/bundler/bundler/blob/89a8778c19269561926cea172acdcda241d26d23/lib/bundler/dependency.rb#L30-L54
+@windows_platforms = [:mswin, :mingw, :x64_mingw]
 
-if version < "4"
-  gem "minitest", "~> 4.7.5"
+# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
+gem 'tzinfo-data', platforms: (@windows_platforms + [:jruby])
+
+group :test do
+  gem 'activerecord'
+  gem 'sqlite3',                          platform: (@windows_platforms + [:ruby])
+  gem 'activerecord-jdbcsqlite3-adapter', platform: :jruby
+
+  gem 'codeclimate-test-reporter', require: false
+  gem 'simplecov', '~> 0.10', require: false, group: :development
+end
+
+group :development, :test do
+  gem 'rubocop', '~> 0.34.0', require: false
 end