CIRCLE WITH A DOT

Main use case I would see:

- selecting HTTP adapter, so you don't end up with 12 different in the project
- choosing markdown renderer
- using nokolexbor instead of nokogiri

@ahx yes. Perhaps RSpec is a bit exotic, but thinking about ActiveRecord, it could:

- set minimal supported AR version as a dependency
- load AR extensions
- even if the project has Sequel in deps, does not load Sequel extensions

Of course, this does not have to be limited to other gems integration, might be also used to turn off some unneeded features (with their dependencies).

Now that we are openly challenging technical status quo around gems, I feel that I can openly share my dream:

gem 'foobar', '>~ 1.0', flags: [:activerecord, :rspec, :phlex]

... which would set up integration with other gems, make them dependencies if needed etc.