Big edit automatically updates parent, better test support

• When using big edit, updating a child will now re-render the parent EDIT record automatically.

For example
rails generate hot_glue:scafold Invoice --big-edit
rails generate hot_glue:scafold LineItem --nested=invioce

Whenever the line item is created, updated, or destroyed, the parent invoice record gets (edit action) re-rendered automatically. This happens for the big edit screen of the invoice.

• Refactors fields into polymoric objects

• Adds test coverage for Postgres Enums

• Fixes tests on CI (and switches to CircleCI)