title: Install APK from site without downloading
body: <p>Until now, I only develop apps for myself or for close friends. <br>
  I don't sell apps so I'm not interested in Google Play. </p>
  
  <p>So, I upload for a personal site I have, give the link to my friends, 
  and they download the APK. <br>
  Next they install the app and delete the APK for saving memory space. </p>
  
  <p>How can I install directly my apps from my site without download the APK? </p>
  
  <p>Thank you</p>