text: Title: New installation does not migrate existing users
  Body: # Description
  When installing into a project, the package functionality does not work with any of the users that already existed before the package was added. Presumably because the existing users aren't added into the `graphql_auth_userstatus` table.
  
  Not sure if this is a bug or new request
  
  # Steps to Reproduce
  
  If we need to reproduce and you don't provide steps for it, it will be closed. Alternatively, you can link a repo with the code to run your issue.
  
  1. Have existing users registered without `django-graphql-auth`
  2. Install `django-graphql-auth` and run migration
  3. Attempt to use any of the functions (i.e., verifyToken)
  
  ## Expected behavior
  
  Attempting to use any of the functions with an existing user should work without any extra steps (or at least minimal extra steps via some sort of management command). Works fine with users created after the fact.
  
  ## Actual behavior
  
  Nothing happens when attempting to use any of the package features for existing users. (i.e., `verifyToken` returns null for token, `sendPasswordResetEmail` does nothing).
  
  # Requirements
  
  ```
  aioredis==1.3.1
  aniso8601==7.0.0
  asgiref==3.2.10
  asn1crypto==1.4.0
  astroid==2.4.2
  async-timeout==3.0.1
  attrs==20.2.0
  autobahn==20.7.1
  Automat==20.2.0
  bcrypt==3.2.0
  blessed==1.17.10
  boto3==1.14.61
  botocore==1.17.61
  cached-property==1.5.1
  cement==3.0.4
  certifi==2020.6.20
  cffi==1.14.2
  channels==2.4.0
  channels-redis==3.1.0
  chardet==3.0.4
  colorama==0.4.3
  constantly==15.1.0
  cryptography==3.1
  daphne==2.5.0
  distro==1.5.0
  Django==3.1.1
  django-cleanup==5.1.0
  django-cors-headers==3.5.0
  django-filter==2.4.0
  django-graphql-auth==0.3.12
  django-graphql-jwt==0.3.0
  django-guardian==2.3.0
  django-polymorphic==3.0.0
  django-storages==1.10
  djangorestframework==3.11.1
  docker==4.3.1
  docker-compose==1.27.2
  docker-pycreds==0.4.0
  dockerpty==0.4.1
  docopt==0.6.2
  docutils==0.16
  graphene==2.1.8
  graphene-django==2.13.0
  graphene-file-upload==1.2.2
  graphql-core==2.3.1
  graphql-relay==2.0.1
  graphql-ws==0.3.0
  hiredis==1.1.0
  hyperlink==20.0.1
  idna==2.10
  importlib-metadata==1.7.0
  incremental==17.5.0
  isort==5.5.2
  jmespath==0.9.4
  jsonschema==3.1.1
  lazy-object-proxy==1.4.2
  mccabe==0.6.1
  more-itertools==7.2.0
  msgpack==0.6.2
  paramiko==2.6.0
  pathspec==0.6.0
  pbr==5.4.3
  Pillow==7.2.0
  promise==2.3
  psycopg2==2.8.6
  pyasn1==0.4.8
  pyasn1-modules==0.2.8
  pycparser==2.20
  PyHamcrest==1.9.0
  PyJWT==1.7.1
  pylint==2.4.4
  PyNaCl==1.3.0
  pyOpenSSL==19.1.0
  pyrsistent==0.15.4
  python-dateutil==2.7.5
  python-dotenv==0.14.0
  pytz==2018.5
  PyYAML==4.2b1
  requests==2.20.0
  Rx==1.6.1
  s3transfer==0.3.3
  semantic-version==2.5.0
  sentry-sdk==0.17.5
  service-identity==18.1.0
  singledispatch==3.4.0.3
  six==1.14.0
  sqlparse==0.3.1
  stevedore==1.30.1
  stripe==2.43.0
  termcolor==1.1.0
  texttable==0.9.1
  Twisted==20.3.0
  txaio==18.8.1
  typed-ast==1.4.0
  Unidecode==1.1.1
  urllib3==1.24.3
  wcwidth==0.1.7
  websocket-client==0.57.0
  wrapt==1.12.1
  zipp==3.1.0
  zope.interface==5.0.0
  ```