Support string pattern in schema

[prvdph]

v 0.2.1

String pattern constraints from schema are not included in docs:

    "birthday": {
      "type": "string",
      "description": "Birthday date in format of mm-dd-yyyy",
      "pattern": "^[0-9]{2}-[0-9]{2}-[0-9]{4}$"
    }

ramlo result:

raml2boot result: