Cannot insert users in psql & mysql databases

This is due to a type mismatch of the permissions column between the model and the table. In the model, permissions is an unsigned int32. However in the database table, the column is a signed int32. Thus, if the value of the permissions field exceeds the maximum value of a signed int32, the database throws an error.

To circumvent this issue, the simplest solution is to change the type of the permissions column to bytea.