Added the ruby gems source in the Gemfile
Renamed the variable grade to "part"
added rspec
Robot movement functionality as a module and its tests
Refactor robot movement to a single line, all tests passing.
Add module with the movement method to the robot class
Remove unuseful parameter reference to robot variable in the movement method.
Merge pull request #1 from inakidelamadrid/master

I'm sorry Manolo for not having created a branch before committing. I hope you can physically test the new code with the arm and may be we can change the call to support changing dynamically the grades variable(e.g 0.5)