title: hosting flask_restplus Swagger UI on Herokuapp says "No API Definition provided."
body: <p>I'm trying to host the Swagger UI of Flask Restplus on Heroku server. It builds successfully and when checked in the logs of the heroku, even there it says "Build succeeded". </p>
  
  <p>But the problem is when I check the actual hosting there's just a msg on the page saying <br>
  <strong>No API definition provided</strong>. </p>
  
  <p><a href="https://i.stack.imgur.com/plUGD.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/plUGD.png" alt="enter image description here"></a>
  Btw the swagger-UI loads successfully on the browser when run locally.</p>
  
  <p>Following is a sample code snipet for swagger-ui<br></p>
  
  <pre class="lang-py prettyprint-override"><code>from flask import Flask
  from flask_restplus import Resource, Api
  import os
  
  app = Flask(__name__)
  api = Api(app)
  
  @api.route('/hello')
  class HelloWorld(Resource):
      def get(self):
          return {'hello': 'world'}
  
  if __name__ == '__main__':
      port = int(os.environ.get("PORT", 5000)) 
      app.run(host="0.0.0.0", port=port, debug=True)
  </code></pre>
  
  <p>So what am I doing wrong here? Is there any way that you can host a simple minimal flask_restplus swagger-UI on <strong>heroku</strong> ? Any help is appreciated, thanks.</p>
  
  <p><strong>EDIT</strong><br></p>
  
  <p>Following is the content of the swagger.json</p>
  
  <pre><code>{
      "swagger": "2.0",
      "basePath": "/",
      "paths": {
          "/hello": {
              "get": {
                  "responses": {
                      "200": {
                          "description": "Success"
                      }
                  },
                  "operationId": "get_hello_world",
                  "tags": [
                      "default"
                  ]
              }
          }
      },
      "info": {
          "title": "API",
          "version": "1.0"
      },
      "produces": [
          "application/json"
      ],
      "consumes": [
          "application/json"
      ],
      "tags": [
          {
              "name": "default",
              "description": "Default namespace"
          }
      ],
      "responses": {
          "ParseError": {
              "description": "When a mask can't be parsed"
          },
          "MaskError": {
              "description": "When any error occurs on mask"
          }
      }
  }
  </code></pre>
  
  <p>Also if it helps, this is what's inside the <code>Procfile</code></p>
  
  <pre><code>web: python app.py
  </code></pre>