title: Swagger validation error on path item: "Additional properties not allowed"
body: <p>I am using <a href="https://www.npmjs.com/package/swagger" rel="noreferrer">https://www.npmjs.com/package/swagger</a> and I am trying to create a config. I have such a part of my swagger.js</p>
  
  <pre><code>       "dummy\/{id}\/related_dummies": {
              "get": {
                  "tags": [
                      "RelatedDummy"
                  ],
                  "operationId": "get_by_parentRelatedDummyCollection",
                  "produces": [
                      "application\/ld+json",
                      "application\/hal+json",
                      "application\/xml",
                      "text\/xml",
                      "application\/json",
                      "text\/html"
                  ],
                  "parameters": [
                      {
                          "name": "id",
                          "in": "path",
                          "required": true,
                          "type": "integer"
                      }
                  ],
                  "summary": "Retrieves the collection of RelatedDummy resources.",
                  "responses": {
                      "200": {
                          "description": "RelatedDummy collection response",
                          "schema": {
                              "type": "array",
                              "items": {
                                  "$ref": "#\/definitions\/RelatedDummy"
                              }
                          }
                      }
                  }
              }
  </code></pre>
  
  <p>But when I run swagger validate swagger.js I keep getting this error:</p>
  
  <pre><code>Project Errors
  --------------
  #/paths: Additional properties not allowed: dummy/{id}/related_dummies
  Results: 1 errors, 0 warnings
  </code></pre>
  
  <p>What could be the reason of the error? Thanks</p>