text: Title: Cyclic imports of db objcect
  Body: I've run flasky with pylint (I can post the specific pylintrc file, if required) and discovered a lot of cyclic imports
  
  ```
  app/auth/__init__.py:1:0: R0401: Cyclic import (app -> app.auth -> app.auth.views -> app.models) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app.auth -> app.auth.views) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app.main -> app.main.views) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app.api -> app.api.users) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app -> app.auth -> app.auth.views) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app -> app.main -> app.main.views -> app.decorators -> app.models) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app -> app.auth -> app.auth.views -> app.email) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app -> app.main -> app.models) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app.main -> app.main.errors) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app -> app.main -> app.main.views -> app.main.forms -> app.models) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app -> app.main -> app.main.views -> app.models) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app -> app.api -> app.api.users -> app.models) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app.api -> app.api.posts -> app.api.decorators -> app.api.errors) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app -> app.api -> app.api.comments -> app.models) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app.api -> app.api.posts -> app.api.errors) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app -> app.api -> app.api.authentication -> app.models) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app -> app.api -> app.api.posts -> app.models) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app -> app.auth -> app.auth.views -> app.auth.forms -> app.models) (cyclic-import)
  app/auth/__init__.py:1:0: R0401: Cyclic import (app -> app.main -> app.main.views) (cyclic-import)
  ```
  Most of them are related to `app.models` module and it doesn't seem to be a good practice.