title: Swagger Schema error should NOT have additional properties
body: <p>I am trying to create swagger json and trying to check it's validity in 
  <a href="http://editor.swagger.io" rel="noreferrer">http://editor.swagger.io</a></p>
  
  <p>Upon validating the json, the above mentioned editor gives the following error:</p>
  
  <pre><code>Schema error should NOT have additional properties
  additionalProperty: components
  Jump to line 0
  </code></pre>
  
  <p>If for some reason I can't define an element named components at root level where i am going to have some sort of json schema, what is the right way to do a $ref on the schema for requestBody for an API operation as I intend to do as seen in my example below. Also, do you see anything wrong with my swagger json ?</p>
  
  <p>My swagger json for swagger2.0 look like this. </p>
  
  <pre><code>{
      "swagger": "2.0",
      "info": {
          "version": "1.0",
          "title": "My swagger API",
          "contact": {
              "name": "myName",
              "email": "abc@gmail.com"
          }
      },
      "host": "localhost:1234",
      "basePath": "/",
      "tags": [{
          "name": "someTagName",
          "description": "this is a try"
      }],
      "components":{"schemas": {"myEndPoint": ""}},
      "paths": {
          "/myEndPoint": {
              "post": {
                  "tags": ["some-tag"],
                  "summary": "myEndPoint endpoint will give you something",
                  "description": "some description will go here",
                  "operationId": "getMyEndPoint",
                  "consumes": ["application/json"],
                  "produces": ["application/json"],
                  "parameters": [{
                      "in": "body",
                      "name": "somePayload",
                      "description": "somePayload is what this is",
                      "required": true,
                      "schema": {
                          "$ref": "#components/schemas/myEndPoint"
                      }
                  },
                  {
                      "in": "header",
                      "name": "Authorization",
                      "description": "auth token goes here",
                      "required": true,
                      "type": "string"
                  }],
                  "responses": {
                      "200": {
                          "description": "Success",
                          "schema": {
                              "type": "string"
                          }
                      },
                      "400": {
                          "description": "Bad Request"
                      }
                  }
              }
          }
      }
  }
  </code></pre>