title: Firebase hosting URL needs .html to display a page
body: <p>I am trying to host a website at Google Firebase.
  The <code>index.html</code> is shown as (e.x.)<code>app.firebase.com</code>, but when I want to access a page like login.html I need to type <code>app.firebase.com/login.html</code>, just <code>app.fire-base.com/login</code> doesn't work. 
  How would I achieve this for every <code>.html</code> file in the directory (public), do I need to configure the <code>firebase.json</code>? I read the docs but I could not find any information.</p>
  
  <p>Here is my .json</p>
  
  <pre><code> {
        "hosting": {
          "public": "public",
          "signin": "/signin.html"
  
        }
      }
  </code></pre>