added mongodb to the dependencies and removed pouchdb related things
started transition to mongodb from couch
added log.txt to gitignore
Merge branch 'dev' into mongo
Adapted login and signup functions for Mongo
backend migrated to mongodb
backend mongo compatability completed
frontend mongo compatability completeted
login working, working out kinks in assignment storing and viewing
Mongodb on backend and frontend fully functional.
Modified README to reflect mongodb migration.