Fix/integrations

[kartik4949]

Description

Related Issues

Checklist

• Is this code covered by new or existing unit tests or integration tests?
• Did you run make unit_testing and make integration-testing successfully?
• Do new classes, functions, methods and parameters all have docstrings?
• Were existing docstrings updated, if necessary?
• Was external documentation updated, if necessary?

Additional Notes or Comments

[blythed]

I think we will have issues parsing t.select(t.brand == 'Nike'), for example. This will require a bit of string wrangling.

[kartik4949]

I tried it, it worked.

[blythed]

I'm not clear why we need to add _schema to the Schema? Maybe you can explain a bit? I would rather say, on insertion, a MongoDB document can optionally specify a _schema, or fall back to the default.