user.js under db missing 'use strict'

[nguyenjk]

the database.js file under db is missing 'use strict' which cause issue "Block-scoped declarations (let, const, function, class) not yet supported outside strict mode" when you try to do db:migrate

[louisrowan]

In addition to this, to get ElephantSQL running I also had to update the config.DatabaseUrl to my ESQL url in Index.js, not just User.js.