Missing relationships

[distributive]

I think we would benefit from having:

• a relationship from cards/printings to their card type (so it can be fetched with an include)
• a relationship from card/printings to restrictions (ditto)

Also some existing relationships are missing their inverses:

• card does not have a hasMany relationship back to card_cycle
• card_cycle, card_set, and card do not have a relationship back to card_pool
• card does not have a relationship back to card_set
• printing does not have a relationship back to card_subtype
• restriction does not have a relationship back to format (I'm not sure if this would be a hasMany or hasOne relationship)
• card_type does not have a relationship back to printing
• card and restriction do not have a relationship back to snapshot

I don't know if all/any of these need implementing, but I think this is all of the missing ones.

[plural]

Completed already:

• card to card_cycle
• card to card_set
• card_cycle and card_set to card_pool
• printing to card_subtypes
• restriction to format
• card_type to printing

still missing:

• card and restriction to snapshot
• card and printing to card pool