Merge pull request #76 from hamstergem/breaking-up-add-spec

We want to standardize and brea up the add spec.
Merge pull request #75 from hamstergem/breaking-up-any-spec

We want to standardize and break up the any spec.
ReduceArguments Rubocop checker is now called SingleLineBlockParams
has_key? -> key?
Fix whitespace
Merge pull request #81 from gcapizzi/fix_rubocop

Make Rubocop happy
Introduce Groupable module