rails directory models and tables

```rb
# table
# - users
# - users_profiles

# app/models/user.rb
class User < ApplicationRecord
end

# app/models/users.rb
module Users
  def self.table_name_prefix
    'users_'
  end
end

# app/models/users/profile.rb
module Users
  class Profile < ApplicationRecord
  end
end
```