pgadmin4 setup.py, first time run

Hi,

When you try to run pgadmin4 for first time(without presence of pgadmin4.db), it ask you to run setup.py. When you run it, it throws python error as follows,
Traceback (most recent call last):
File "/home/test/Development/pgadmin4/web/setup.py", line 145, in <module>
do_setup(app)
File "/home/test/Development/pgadmin4/web/setup.py", line 57, in do_setup
user_datastore.add_role_to_user(email, 'Administrators')
File "/usr/local/lib/python2.7/dist-packages/Flask_Security-1.7.4-py2.7.egg/flask_security/datastore.py", line 106, in add_role_to_user
if role not in user.roles:
AttributeError: 'NoneType' object has no attribute 'roles'

It's because,user_datastore.create_role,user_datastore.create_user and user_datastore.add_role_to_user all calls are for in one database transaction. It need to commit it after first two calls or creating role and user for add_role_to_user to work,

Find attached patch for this.

regards,
Prasad Somwanshi