Introduce PushMessageReceiver and set up manifest.

app/src/fdroid/AndroidManifest.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <application
+        android:name=".Amethyst">
+
+        <receiver
+            android:exported="true"
+            android:enabled="true"
+            android:name=".service.notifications.PushMessageReceiver">
+            <intent-filter>
+                <action android:name="org.unifiedpush.android.connector.MESSAGE"/>
+                <action android:name="org.unifiedpush.android.connector.UNREGISTERED"/>
+                <action android:name="org.unifiedpush.android.connector.NEW_ENDPOINT"/>
+                <action android:name="org.unifiedpush.android.connector.REGISTRATION_FAILED"/>
+                <action android:name="org.unifiedpush.android.connector.REGISTRATION_REFUSED"/>
+            </intent-filter>
+        </receiver>
+
+    </application>
+
+</manifest>

app/src/fdroid/java/com/vitorpamplona/amethyst/service/notifications/PushMessageReceiver.kt

@@ -0,0 +1,27 @@
+package com.vitorpamplona.amethyst.service.notifications
+
+import android.content.Context
+import android.content.Intent
+import org.unifiedpush.android.connector.MessagingReceiver
+
+class PushMessageReceiver: MessagingReceiver() {
+    override fun onMessage(context: Context, message: ByteArray, instance: String) {
+        super.onMessage(context, message, instance)
+    }
+
+    override fun onNewEndpoint(context: Context, endpoint: String, instance: String) {
+        super.onNewEndpoint(context, endpoint, instance)
+    }
+
+    override fun onReceive(context: Context, intent: Intent) {
+        super.onReceive(context, intent)
+    }
+
+    override fun onRegistrationFailed(context: Context, instance: String) {
+        super.onRegistrationFailed(context, instance)
+    }
+
+    override fun onUnregistered(context: Context, instance: String) {
+        super.onUnregistered(context, instance)
+    }
+}