FEATURE: Opt-in native Discourse app install banner on Android/iOS

app/controllers/metadata_controller.rb

@@ -13,7 +13,7 @@ class MetadataController < ApplicationController
   private
 
   def default_manifest
-    {
+    manifest = {
       name: SiteSetting.title,
       short_name: SiteSetting.title,
       display: 'standalone',
@@ -29,5 +29,19 @@ class MetadataController < ApplicationController
         }
       ]
     }
+
+    if SiteSetting.native_app_install_banner
+      manifest = manifest.merge({
+        prefer_related_applications: true,
+        related_applications: [
+          {
+            platform: "play",
+            id: "com.discourse"
+          }
+        ]
+      })
+    end
+
+    manifest
   end
 end

app/views/layouts/application.html.erb

@@ -47,6 +47,10 @@
     <%= render_google_universal_analytics_code %>
     <link rel="manifest" href="<%= Discourse.base_uri %>/manifest.json">
 
+    <%- if SiteSetting.native_app_install_banner? %>
+        <meta name="apple-itunes-app" content="app-id=1173672076">
+    <%- end %>
+
     <%= yield :head %>
   </head>
 

config/locales/server.en.yml

@@ -1367,6 +1367,8 @@ en:
 
     topic_page_title_includes_category: "Topic page title includes the category name."
 
+    native_app_install_banner: "Asks recurring visitors to install Discourse native app."
+
     max_prints_per_hour_per_user: "Maximum number of /print page impressions (set to 0 to disable)"
 
     full_name_required: "Full name is a required field of a user's profile."

config/site_settings.yml

@@ -1260,6 +1260,8 @@ uncategorized:
 
   topic_page_title_includes_category: true
 
+  native_app_install_banner: false
+
 
 user_preferences:
   default_email_digest_frequency: