Remove Gemfile.lock from gitignore

In order to ensure the correct versions of gems are used in this
cookbook, this commit removes the Gemfile.lock from the gitignore. It
also commits the current Gemfile.lock.

[24820]
Merge branch 'master' into 24820-remove-gemfilelock-from-gitignore-in-rubycas

* master:
  Add MIT license

Conflicts:
	metadata.rb
Merge pull request #27 from sqm/24820-remove-gemfilelock-from-gitignore-in-rubycas

#24820 - Remove Gemfile.lock from gitignore