gemfile

I often see the following notation(~>) in Gemfile. gem "cucumber", "~>0.8.5" gem "rspec", "~>1.3.0" I know the sign (>=) is just greater or equal to, but what does the (~>) notation mean? Are they both same or has any significant difference? That's a pessimistic version constraint . RubyGems will increment the last digit in the version provided and use that until it reaches a maximum version. So ~>0.8.5 is semantically equivalent to: gem "cucumber", ">=0.8.5", "<0.9.0" The easy way to think about it is that you're okay with the last digit incrementing to some arbitrary value, but the ones

Gem::LoadError Specified 'mysql2' for database adapter, but the gem is not loaded. Add `gem 'mysql2'` to your Gemfile This error occurred while loading the following files: active_record/base This is the error I get on running rails server. The mysql2 gem has been added to the Gemfile as well. I've done bundle install , and tried restarting the server but still get the error. Hassan Azimi If you have this error when upgrading to rails 4.2.4 (also with rails 4.1.5) try using this version of mysql2: gem 'mysql2', '~> 0.3.18' Apparently mysql2 isn't still compatible with newer version of rails

I am a beginner to Ruby on Rails and I am using Rails 3.0.9. What is the difference between Gemfile and Gemfile.lock in Rails? Dylan Markow The Gemfile is where you specify which gems you want to use, and lets you specify which versions. The Gemfile.lock file is where Bundler records the exact versions that were installed. This way, when the same library/project is loaded on another machine, running bundle install will look at the Gemfile.lock and install the exact same versions, rather than just using the Gemfile and installing the most recent versions. (Running different versions on

What is the use of Gemfile in rails? How to use Gemfile ? During your development in Rails, there will be times where you will want to provide some functionality which is required by you, but either you don't know how to do or you don't want to implement it on your own since a lot of work has been put into its development by talented developers. These developments which you might need (user authentication, message system, asset handlers, geolocation, pagination system, linking to exterior services such as Amazon AWS, and last but not least Rails itself) are called Ruby Gems. These are ruby