User should be logged in before creating repo

- We need current user's id while creating a repo.
- Added before_filter authenticate_user! constraint for "new, create,
  edit and update" actions.
- Added test cases for verifying that non-logged in user can't create
  the repo and logged in user can create the repo.
- Closes #273
Bump excon and webmock to remove "Invalid Excon request keys" warning

- Hopefully this will make travis :green:
Updated test to use refinerycms
Use VCR cassete so tests will pass on travis
Merge pull request #277 from codetriage/user-should-be-logged-in-before-creating-repo

User should be logged in before creating repo