title: twitter PWA doesn't open in native-app like setting
body: <p>I am new to PWA and super excited about this. Sorry, this question is not technical at all, but I wanted to demo a successful PWA in the market to people at my work. And I have saved twitter to my home screen on my iPhone, and when I click it on the home screen to open the PWA, it automatically opens in safari browser.. 
  Can someone please tell me how I can open twiter app in PWA? 
  To make sure it's not my phone's problem, I saved the below PWA on my phone and this opens as a native app like setting: <a href="https://angular2-hn.firebaseapp.com/news/1" rel="nofollow noreferrer">https://angular2-hn.firebaseapp.com/news/1</a></p>
  
  <p>Thanks so much and sorry for asking stupid non-technical question here...
  I googled everywhere but couldn't find a similar question being asked anywhere. </p>