Add more postgres support (#2080)

* reload the right data

More passing postgres tests

Handle schema updates, and $in for non array columns

remove authdata from user and implement ensureUniqueness

Make some tests work, detect existing classes

Throw proper error for unique index violation

* fix findOneAndUpdate

spec/Schema.spec.js

@@ -788,11 +788,10 @@ describe('SchemaController', () => {
       _id: '_User',
       username: { type: 'String' },
       password: { type: 'String' },
-      authData: { type: 'Object' },
       email: { type: 'String' },
       emailVerified: { type: 'Boolean' },
     },{
-      authData: { type: 'String' },
+      emailVerified: { type: 'String' },
       customField: { type: 'String' },
     })).toEqual({
       customField: { type: 'String' }