Bundler makes it very easy to point to a gem folder on your system, and I definitely recommend this approach a lot more. The plugin can be a gem that we can just require, and it can specify its own dependencies in its .gemspec file.

But if you really don’t want your plugin to be a gem, for whatever reason, then read on…

If we are developing a Spree extension, or a Retrospectiva extension, or a Fat Free CRM plugin, we might sometimes need a way to require the gems in multiple Gemfiles, but Bundler doesn’t cater for this. The best solution I came up with is this:

1. Add a Gemfile file to the root of your plugin or extension, and specify the gems you need in the normal way.
2. Add the following code to the bottom of your root Gemfile (in your main Rails app):

# Install gems from each plugin

Dir.glob(File.join(File.dirname(**FILE**), 'vendor', 'plugins', '\*\*', "Gemfile")) do |gemfile|
eval(IO.read(gemfile), binding)
end

This will find and evaluate the Gemfiles from each of your plugins/extensions, as if you were modifying your base Gemfile.