Find a way to commit Investigation information to the database

[tomchop]

Links drawn during investigations are very valuable, let's find a way to incorporate this into Yeti's main DB.

Example use cases:

• Several reports (investigations) tied to one actor. It would be cool to have a list of related investigations, and see where observables come from.
• Leverage this information when Searching & Adding observables

[axpatito]

+1

[haxpak]

+1