Question

I’m learning Ruby on Rails using this excellent tutorial, and I noticed that the author always specifies the Gem version number in the Gemfile (see here, here, and here). Is this something I should get in the habit of doing? If so, how do I know what version to specify?

Answer 1

I suggest to not specify the gem version, until you have found an incompatibility with a specific gem.

Bundler will itself lock a specific versions of the gems. You just need to remember to use bundle install --deployment on the production machine(s), and make upgrades only on your development machine (or in another directory).

It will be very important to have a good test coverage of your project. Without tests, you will not know when an upgrade breaks your application. I humbly suggest the following route:

• run rake test (just to be sure that everything works)
• run bundle update
• run rake test

If the test passes, commit the change in Gemfile.lock. If the test does not pass, and you want to lock a given gem, then specify the version in Gemfile.

You may read about install –deployment and deploying in the bundler documentation.