RFC: Do not generate associations for _id fields if no Table object or database table present

[ajibarra]

Description

When baking a model, if you database table has a field with _id suffix it generates a belongsTo association. It is usually useful but sometimes it is not an actual association.

i.e A users table with an external_id to store the user id in another app/service.

Currently Bake would generate a belongsTo association with Externals as alias, even if ExternalsTable does not exist and externals table does not exist onto database.

I would propose to only generate the association if any of the above conditions is met.

I have a partial solution already but I would like to know your thoughts.

[othercorey]

This seems like #834

[ajibarra]

This seems like #834

I have created this one after working on #834 . However I understood the problem in that one was about validation and not the association itself. Please let me know if I misunderstood.

Anyway I can prepare a PR this week to avoid creating associations to table that does not exist.

[othercorey]

The invalid association is a side-effect of the bug overall. However, removing an invalid association was simple compared to re-adding missing validation.