Perhaps looking at a working many-to-many example might help.  Flask-Security is a great one.

https://pythonhosted.org/Flask-Security/quickstart.html#sqlalchemy-application

Flask-SQLAlchemy many-to-many ordered relationship in hybrid_property
I see an increasing demand for an unlike button on Facebook: 


http://www.facebook.com/pages/The-Unlike-Button/72641866357
Facebook Adds An Unlike Button For Pages
May 7, 2010
Facebook "Unlike" Button Comes to the News Feed
NOV 3, 2010


I have always used and understood unlike in the sense of dissimilar. Is it ever used in the sense of do not like?    
