Change all model relations to use the ORM

[tommarmstrong]

Some relations between objects are mapped using username or course code fields instead of allowing the ORM to handle relations. This has caused issues #31 and #51.

Using the ORM will make reasoning about relations much more straightforward, remove issues like those mentioned above and mean that the DB is better normalised.

[zwaters]

I agree - thanks Tomm!

Things like the learning records could also stand to become linked (to the user model) to avoid learning records living in "limbo" once a user is deleted or their name is changed. There was a reason why that wasn't the case in the first place, but I cannot remember now..

[tommarmstrong]

@zwaters, it can always be set up so that users don't get deleted just made inactive. Not sure if there are any ethical concerns around this though...

[tommarmstrong]

Models to be updated

• Learning record
• OAuth flow temp
• Social relationship
• Cached content
• Access log
• User classification
• Dashboard reflection
• Group map
• Comment
• Video

[kojiagile]

Tables that are updated (in LRSIntegration branch)
clatoolkit_learningrecord
clatoolkit_oauthflowtemp
clatoolkit_socialrelationship
clatoolkit_cachedcontent
clatoolkit_dashboardreflection