Remove rudiment "Model" part at models naming 

That common convention at django world.
https://docs.djangoproject.com/en/3.0/topics/db/models/

For example:
https://github.com/perfguru87/panopticum/blob/master/panopticum/models.py#L13

```class CountryModel(models.Model):```

to

```class Country(models.Model):```