group :development do
  # Use rspec-rails to run test environment
  gem 'rspec-rails'
end

Failure/Error: require File.expand_path('../../config/environment', __FILE__)

Gem::LoadError:
  You have already activated rspec-support 3.6.0.beta2, but your Gemfile requires rspec-support 3.5.0. Prepending `bundle exec` to your command may solve this.

gem uninstall rspec-3.6.0.beta2