Merge pull request #121 from nrobeR/master

(feat) Create routes to return recent campaigns
(refactor) Clean up ab_test folder
add testing for queries
(test) add additional testing for ab_test queries and add image test route
(Debug) Fix rebase conflicts
(Debug) Fix variable name inconsistency
Merge pull request #122 from armandopmj/feat/ABtestingRouts

(test) add additional testing for ab_test queries and add image test route
(cleanup) Cleanup the db connection require code