message: add 'file' to schema for body parameters
diff: "default": {}
  },
  "type": {
  + "oneOf": [
  + {
  "$ref": "http://json-schema.org/draft-04/schema#/properties/type"
  },
  + {
  + "type" : "string",
  + "enum" : ["file"]
  + }
  + ]
  + },
  "items": {
  "anyOf": [
  {
  