Added Receipt model and Controller, and the basic get for it. Also added validation for PATCH user when changing the password, it requires and 'oldPassword' field now and removed models we weren't using nor requiring at the moment to avoid confusion and leave room for a better implementation later on. [CRP-47, CR¨-42. CRP-30]
Merge pull request #5 from Heart-Code/feature/CRP-47

[CRP-47, CRP-42, CRP-30]