Django Upgrade to 2.2.28

Following the upgrade of django 2.0 I attempted to upgrade to django 2.1 and faced an issue with the database. I did some research online and they recommended just upgrading directly to 2.2 but this unfortunately did not fix the issue. It seems as though there are duplicate entries in the database for an unknown reason (possibly due to modifications in the permissions that were necessary).

This is the most recent traceback:
```
Traceback (most recent call last):
File "/usr/local/lib/python3.7/site-packages/django/db/backends/utils.py", line 84, in _execute
return self.cursor.execute(sql, params)
psycopg2.errors.UniqueViolation: duplicate key value violates unique constraint "auth_permission_content_type_id_codename_01ab375a_uniq"
DETAIL: Key (content_type_id, codename)=(4, view_user) already exists.

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "manage.py", line 10, in
execute_from_command_line(sys.argv)
File "/usr/local/lib/python3.7/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
utility.execute()
File "/usr/local/lib/python3.7/site-packages/django/core/management/__init__.py", line 375, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/usr/local/lib/python3.7/site-packages/django/core/management/base.py", line 323, in run_from_argv
self.execute(*args, **cmd_options)
File "/usr/local/lib/python3.7/site-packages/django/core/management/base.py", line 364, in execute
output = self.handle(*args, **options)
File "/usr/local/lib/python3.7/site-packages/django/core/management/base.py", line 83, in wrapped
res = handle_func(*args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/django/core/management/commands/migrate.py", line 257, in handle
self.verbosity, self.interactive, connection.alias, apps=post_migrate_apps, plan=plan,
File "/usr/local/lib/python3.7/site-packages/django/core/management/sql.py", line 51, in emit_post_migrate_signal
**kwargs
File "/usr/local/lib/python3.7/site-packages/django/dispatch/dispatcher.py", line 175, in send
for receiver in self._live_receivers(sender)
File "/usr/local/lib/python3.7/site-packages/django/dispatch/dispatcher.py", line 175, in
for receiver in self._live_receivers(sender)
File "/code/Rodan/rodan/models/__init__.py", line 61, in add_view_user_permission
Permission.objects.get_or_create(codename='view_user', name='View User', content_type=content_type)
File "/usr/local/lib/python3.7/site-packages/django/db/models/manager.py", line 82, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/django/db/models/query.py", line 541, in get_or_create
return self._create_object_from_params(kwargs, params)
File "/usr/local/lib/python3.7/site-packages/django/db/models/query.py", line 583, in _create_object_from_params
raise e
File "/usr/local/lib/python3.7/site-packages/django/db/models/query.py", line 575, in _create_object_from_params
obj = self.create(**params)
File "/usr/local/lib/python3.7/site-packages/django/db/models/query.py", line 422, in create
obj.save(force_insert=True, using=self.db)
File "/usr/local/lib/python3.7/site-packages/django/db/models/base.py", line 744, in save
force_update=force_update, update_fields=update_fields)
File "/usr/local/lib/python3.7/site-packages/django/db/models/base.py", line 782, in save_base
force_update, using, update_fields,
File "/usr/local/lib/python3.7/site-packages/django/db/models/base.py", line 873, in _save_table
result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
File "/usr/local/lib/python3.7/site-packages/django/db/models/base.py", line 911, in _do_insert
using=using, raw=raw)
File "/usr/local/lib/python3.7/site-packages/django/db/models/manager.py", line 82, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/django/db/models/query.py", line 1186, in _insert
return query.get_compiler(using=using).execute_sql(return_id)
File "/usr/local/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1377, in execute_sql
cursor.execute(sql, params)
File "/usr/local/lib/python3.7/site-packages/django/db/backends/utils.py", line 67, in execute
return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
File "/usr/local/lib/python3.7/site-packages/django/db/backends/utils.py", line 76, in _execute_with_wrappers
return executor(sql, params, many, context)
File "/usr/local/lib/python3.7/site-packages/django/db/backends/utils.py", line 84, in _execute
return self.cursor.execute(sql, params)
File "/usr/local/lib/python3.7/site-packages/django/db/utils.py", line 89, in __exit__
raise dj_exc_value.with_traceback(traceback) from exc_value
File "/usr/local/lib/python3.7/site-packages/django/db/backends/utils.py", line 84, in _execute
return self.cursor.execute(sql, params)
django.db.utils.IntegrityError: duplicate key value violates unique constraint "auth_permission_content_type_id_codename_01ab375a_uniq"
DETAIL: Key (content_type_id, codename)=(4, view_user) already exists.
```