Fix for related query on non-existing column

[gfosco]

This will finally address #280 and #286.

[flovilmart]

The role is expected to have a relation to users in the schema, mind to add the same test with a random object, and non existing relation key?

[drew-gross]

I agree with @flovilmart, I don't think the test you added actually tests this change. That said, it's also a simple change so I'd say feel free to merge anyway. (test failure is just flakiness)

[gfosco]

The test fails without the change, so it does work..

[codecov-io]

Current coverage is 91.87%

Merging #861 into master will increase coverage by +0.19% as of 5b7353e

@@            master    #861   diff @@
======================================
  Files           71      71       
  Stmts         4102    4454   +352
  Branches       845    1012   +167
  Methods          0       0       
======================================
+ Hit           3761    4092   +331
- Partial         10      12     +2
- Missed         331     350    +19

Review entire Coverage Diff as of 5b7353e

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[drew-gross]

Actually that does make sense, since the relation will only be in the _SCHEMA object, the collection won't actually be created.

[flovilmart]

oh right !