Refactor/data base

[vitormpp]

Closes #835

Review checklist

• [ ] Terms and conditions reflect the current change
• [ ] Contains enough appropriate tests
• [ ] If aimed at production, writes a new summary in whatsnew/whatsnew-pt-PT
• [ ] Properly adds an entry in changelog.md with the change
• [ ] If PR includes UI updates/additions, its description has screenshots
• [ ] Behavior is as expected
• [ ] Clean, well-structured code

[bdmendes]

@vitormpp is this ready?

[bartekpacia]

@vitormpp Could you rebase/merge with the master branch? I could then try to help you debug it.