How can I create a realationship between something like tasks and projects?

I wrote a guide (like @Gorro_Rojo said) for this some days ago. Check it out.
As @Gorro_Rojo said and is written in the last Sprint review (53) Collections will make it easier.

Collections :duck::duck::duck::duck::duck:
It’s Sets with a twist: you can choose what’s in :inbox_tray: and what’s out :outbox_tray: . Manually reorder with drag-'n-drop, remove multiple Objects from your Collection, or completely delete them from your account, it’s all up to
you! :index_pointing_at_the_viewer: