Code review comment for lp:~akretion-team/partner-contact-management/add-partner_relation

Sorry Alexis for my late reply! Meanwhile, we added quite a bit to our approach to partner relations, so I made an alternative MP: https://code.launchpad.net/~therp-nl/partner-contact-management/7.0_partner_relations/+merge/223734

The differences are: We use views to duplicate data instead of code, I personally like this approach more. Then we also enable restrictions on the operands of a relation, and some data (validity date, active) on the relation itself.

Further, I took some care that it is simple to search for partners using relations they have among each other.