Improve error message for invalid login request.
Add CORS middleware.
Rename User.findSynth to findSynthByName.
Add findAllSynths to User.
Use instance method instead of static method for removing Synths.
Use passport-local-mongoose to implement authentication.
Remove unused User methods and statics.
Fix error handling/reporting in tests.
Strip model metadata (_id, __v) from objects before converting to JSON.
Improve creation and updating of chars to include more fields.