Can't add users via UI when using Postgres backend

[greenape]

Clicking the + button to add a new user in FlowAuth, when using a Postgres backend, bounces you back to the login screen.

Actual behind the scenes error:

flowauth_1                           | [2019-04-15 14:36:52,204] ERROR in app: Exception on /admin/users/false/groups [GET]
flowauth_1                           | Traceback (most recent call last):
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/sqlalchemy/engine/base.py", line 1244, in _execute_context
flowauth_1                           |     cursor, statement, parameters, context
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/sqlalchemy/engine/default.py", line 552, in do_execute
flowauth_1                           |     cursor.execute(statement, parameters)
flowauth_1                           | psycopg2.errors.InvalidTextRepresentation: invalid input syntax for integer: "false"
flowauth_1                           | LINE 3: WHERE "user".id = 'false'
flowauth_1                           |                           ^
flowauth_1                           |
flowauth_1                           |
flowauth_1                           | The above exception was the direct cause of the following exception:
flowauth_1                           |
flowauth_1                           | Traceback (most recent call last):
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 2292, in wsgi_app
flowauth_1                           |     response = self.full_dispatch_request()
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1815, in full_dispatch_request
flowauth_1                           |     rv = self.handle_user_exception(e)
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1718, in handle_user_exception
flowauth_1                           |     reraise(exc_type, exc_value, tb)
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/flask/_compat.py", line 35, in reraise
flowauth_1                           |     raise value
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1813, in full_dispatch_request
flowauth_1                           |     rv = self.dispatch_request()
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1799, in dispatch_request
flowauth_1                           |     return self.view_functions[rule.endpoint](**req.view_args)
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/flask_login/utils.py", line 261, in decorated_view
flowauth_1                           |     return func(*args, **kwargs)
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/flask_principal.py", line 199, in _decorated
flowauth_1                           |     rv = f(*args, **kw)
flowauth_1                           |   File "./flowauth/admin.py", line 777, in get_user_groups
flowauth_1                           |     user = User.query.filter(User.id == user_id).first_or_404()
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/flask_sqlalchemy/__init__.py", line 425, in first_or_404
flowauth_1                           |     rv = self.first()
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/sqlalchemy/orm/query.py", line 3215, in first
flowauth_1                           |     ret = list(self[0:1])
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/sqlalchemy/orm/query.py", line 3007, in __getitem__
flowauth_1                           |     return list(res)
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/sqlalchemy/orm/query.py", line 3317, in __iter__
flowauth_1                           |     return self._execute_and_instances(context)
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/sqlalchemy/orm/query.py", line 3342, in _execute_and_instances
flowauth_1                           |     result = conn.execute(querycontext.statement, self._params)
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/sqlalchemy/engine/base.py", line 988, in execute
flowauth_1                           |     return meth(self, multiparams, params)
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/sqlalchemy/sql/elements.py", line 287, in _execute_on_connection
flowauth_1                           |     return connection._execute_clauseelement(self, multiparams, params)
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/sqlalchemy/engine/base.py", line 1107, in _execute_clauseelement
flowauth_1                           |     distilled_params,
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/sqlalchemy/engine/base.py", line 1248, in _execute_context
flowauth_1                           |     e, statement, parameters, cursor, context
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/sqlalchemy/engine/base.py", line 1466, in _handle_dbapi_exception
flowauth_1                           |     util.raise_from_cause(sqlalchemy_exception, exc_info)
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/sqlalchemy/util/compat.py", line 383, in raise_from_cause
flowauth_1                           |     reraise(type(exception), exception, tb=exc_tb, cause=cause)
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/sqlalchemy/util/compat.py", line 128, in reraise
flowauth_1                           |     raise value.with_traceback(tb)
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/sqlalchemy/engine/base.py", line 1244, in _execute_context
flowauth_1                           |     cursor, statement, parameters, context
flowauth_1                           |   File "/usr/local/lib/python3.7/site-packages/sqlalchemy/engine/default.py", line 552, in do_execute
flowauth_1                           |     cursor.execute(statement, parameters)
flowauth_1                           | sqlalchemy.exc.DataError: (psycopg2.errors.InvalidTextRepresentation) invalid input syntax for integer: "false"
flowauth_1                           | LINE 3: WHERE "user".id = 'false'
flowauth_1                           |                           ^
flowauth_1                           |
flowauth_1                           | [SQL: SELECT "user".id AS user_id, "user".username AS user_username, "user"._password AS user__password, "user".is_admin AS user_is_admin
flowauth_1                           | FROM "user"
flowauth_1                           | WHERE "user".id = %(id_1)s
flowauth_1                           |  LIMIT %(param_1)s]
flowauth_1                           | [parameters: {'id_1': 'false', 'param_1': 1}]
flowauth_1                           | (Background on this error at: http://sqlalche.me/e/9h9h)

[greenape]

Route being hit is GET /admin/users/false