Support json schema for enum

[rvp-diconium]

When declaring an enum type in a json schema file:

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "Foo",
  "type": "string",
  "enum": [
    "OPTION_1",
    "OPTION_1"
  ]
}

The enum it is not getting generated, should support it