More improvements

[shime]

Here's a new set of improvements by @mivanek and me, as promised in #7.

Some of the added features include:

• accept multiple gems at once
• accept a gemfile which will be used
• removal of unnecessary stuff from Gemfile
• removal of unnecessary folder from version control
• new class for argument parsing
• new runner class
• messages are extracted into seperate module
• use a class for dealing with gems (some methods from runner should probably be moved there)
• cover everything with tests

What would be nice to have:

• --no-version option, adds into gemfile without fetching latest version
• --version option for specifying version
• --no-install option, skips bundle
• --environment option, accepts multiple environments
• check if the gem's already been included inside gemfile
• force new version of a gem
• global ~/.gemrat.yml and local .gemrat.yml

@mivanek is currently working on adding the option parser to Arguments.

Thanks for the great gem!

[DruRly]

Once again, it looks great man! Updated README coming soon

[shime]

:+1: :beers: