chore(models): remove mongo/User from index

MongoDB User model deleted — all user lookups now go through MySQL.

src/database/models/mongo/index.js

@@ -1,4 +1,3 @@
-exports.User = require('./User');
 exports.Application = require('./Application');
 exports.Aeronef = require('./Aeronef');
 exports.Canopy = require('./Canopy');