Gemfile in gretel-3.0.9 vs Gemfile in gretel-4.0.0

@@ -1,23 +1,6 @@
 source "http://rubygems.org"
 
-# Declare your gem's dependencies in gretel.gemspec.
-# Bundler will treat runtime dependencies like base dependencies, and
-# development dependencies will be added by default to the :development group.
 gemspec
 
-# Declare any dependencies that are still in development here instead of in
-# your gemspec. These might include edge Rails or gems from your path or
-# Git. Remember to move these dependencies to your gemspec before releasing
-# your gem to rubygems.org.
-
-# To use debugger
-# gem 'debugger'
-
-group :development do
-  # jquery-rails is used by the dummy application
-  gem "jquery-rails"
-end
-
-group :test do
-  gem 'test-unit', '~> 3.0' if RUBY_VERSION >= "2.2"
-end
+rails_version = ENV['RAILS_VERSION'] || '>= 0'
+gem 'rails', rails_version