Authorization with CanCan

I continued refactoring Voluntary to replace user by polymorphic resource association for vacancy and candidature models and got blocked when I tried to prove the refactoring in development mode so I had to wait for Mathias.

Meanwhile I continued working on my small application translate_german_words. It was about refactoring the part that saves the translation in a file. I only have one error and then this part is finished.

As Mathias arrived we found and handled the error source in a hidden authorization logic issue caused by the refactoring.
At this opportunity he explained to me the authorization solution CanCan. 
We finished the refactoring and proved the integration of it by tests.

Positive things of the day:

• Ran in circles with the block in Voluntary, but now I know much better the application
• Can see the importance of having tests. I don't have tests for my small application and I think the changes could be easier with the tests.