Feat: Completed backend entities

[MrAnyx]

Description

• Completed the backend with entities :

  • Tag
  • Topic
  • Classifier
  • Article
  • Moodline
  • Publication

• Created tests

• Created fixtures

• Created Exceptions

Type of changes

• Bug fix
• New feature
• Major update
• Minor update

Screenshots

Checklist

Check that each item in the following list is respected before performing a merge

• The description of the change is correctly filled in
• Screenshots are attached in the corresponding section if a page has been visually modified or added
• No conflicts between branches
• The merge request is created from the right branch and targets the right branch
• Code is correctly factored (no code duplication)
• Variable and function names make sense
• There are enough comments when the code is complicated
• The indentation of the code is correct
• Unit and function tests have been updated
• Unit and function tests are always valid