I've installed will_paginate with Gem and Bundle; now I see there's an update on GitHub (this commit) -- How can I update it? Manually? Reinstall it with git clone?
You want bundle update
You can add the gem name if you want to update a specific one with bundle update will_paginate
Here's a more detailed tutorial: http://gembundler.com/rationale.html
You want the subsection called "Updating a Gem Without Modifying the Gemfile".
If you have included the gem in the Gemfile with a git path (and you haven't included any directive that would prevent an update like a version number), it will update the gem based on the source provided. You'll need to do this everywhere. Updates are not synchronized with your application's version control.
Here is a guide specific to git: http://gembundler.com/git.html
If you only want a specific commit, you're going to need to add a :ref argument with the hash.