This error had happen after I do migrate Applying posts.0002_post_user...Traceback (most recent call last): File "manage.py", line 15, in execute_from_command_line(sys.argv) File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line utility.execute() File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/core/management/__init__.py", line 375, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/core/management/base.py", line 316, in run_from_argv self.execute(*args, **cmd_options) File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/core/management/base.py", line 353, in execute output = self.handle(*args, **options) File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/core/management/base.py", line 83, in wrapped res = handle_func(*args, **kwargs) File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/core/management/commands/migrate.py", line 203, in handle fake_initial=fake_initial, File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/db/migrations/executor.py", line 117, in migrate state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial) File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/db/migrations/executor.py", line 147, in _migrate_all_forwards state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial) File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/db/migrations/executor.py", line 244, in apply_migration state = migration.apply(state, schema_editor) File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/db/migrations/migration.py", line 124, in apply operation.database_forwards(self.app_label, schema_editor, old_state, project_state) File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/db/migrations/operations/fields.py", line 84, in database_forwards field, File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/db/backends/sqlite3/schema.py", line 300, in add_field self._remake_table(model, create_field=field) File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/db/backends/sqlite3/schema.py", line 172, in _remake_table self.effective_default(create_field) File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/db/backends/base/schema.py", line 239, in effective_default return field.get_db_prep_save(default, self.connection) File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/db/models/fields/related.py", line 937, in get_db_prep_save return self.target_field.get_db_prep_save(value, connection=connection) File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/db/models/fields/__init__.py", line 790, in get_db_prep_save return self.get_db_prep_value(value, connection=connection, prepared=False) File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/db/models/fields/__init__.py", line 956, in get_db_prep_value value = self.get_prep_value(value) File "/Users//Desktop/Work/Python/django-project/lib/python3.7/site-packages/django/db/models/fields/__init__.py", line 965, in get_prep_value return int(value) ValueError: invalid literal for int() with base 10: 'auth.User'