Adding of new expert and author

[tietotuomas]

As a user,
I want appoint an author and an expert to a certain taxonomy

---

Acceptance Criteria

• site contains a form for adding experts (rename/modify author form to expert form)
• expert is related to one or more taxonomic unit (requires remodeling existing models, especiall expert and TaxonomicUnit?)
• appoint expert to a certain taxonomy/taxon/taxa (dropdown)
• field for adding an author on add-taxa form

---

Ready when:

• Feature is implemented according to the Acceptance Criteria and it works as intended
• Documentation regarding the feature is written
• Code follows the agreed styling
• Code is reviewed (by 2 individuals other than the coder)
• Feature is merged into main and is on stating
• Feature is in production