Description:
    Stubs out a new experiment and its variants. Pass the experiment name,
    either CamelCased or under_scored, and a list of variants as arguments.

    To create an experiment within a module, specify the experiment name as a
    path like 'parent_module/experiment_name'.

    This generates an experiment class in app/experiments and invokes feature
    flag, and test framework generators.

Example:
    `rails generate gitlab:experiment NullHypothesis control candidate alt_variant`

    NullHypothesis experiment with default variants.
        Experiment:   app/experiments/null_hypothesis_experiment.rb
        Feature Flag: config/feature_flags/experiment/null_hypothesis.yaml
        Test:         test/experiments/null_hypothesis_experiment_test.rb
