Added foreground permission

Closes #50

FAQ.md

@@ -11,6 +11,7 @@ Frequently Asked Questions
 * View network connections (ACCESS_NETWORK_STATE): to monitor internet connectivity changes
 * Run at startup (RECEIVE_BOOT_COMPLETED): to start monitoring on device start
 * Optional: read your contacts (READ_CONTACTS): to autocomplete addresses
+* ... (FOREGROUND_SERVICE): to run a foreground service on Android 9 Pie and later, see also the next question.
 
 <a name="FAQ2"></a>
 **(2) Why is there a permanent notification shown?**

app/src/main/AndroidManifest.xml

@@ -6,6 +6,7 @@
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
     <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
     <uses-permission android:name="android.permission.READ_CONTACTS" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
 
     <application
         android:name=".ApplicationEx"