From episode "5 - Setting Up Universal Links (Deep Linking)" on the Inside iOS Dev Podcast
1) Create an apple-app-site-association file that contains JSON data about the URLs that your app can handle.
-  Create 
apple-app-site-associationtext file without.jsonfile extension -  Use 
application/jsonMIME type for the text file -  Have the following contents of the file similar to this format:
{ "applinks": { 
"apps": [],