TheOdinProject/curriculum — pull request #358 by donaldali (2014-07-16 05:32:39+00:00)
Title: Fix Source associations

I couldn't get this set of associations to work as is. After some googling I found out about the extra `:foreign_key` options; everything worked fine after I added the changes I made here.
If the associations work as they were and I missed something then I apologize, but I think these additions are needed.