Create installation.android.md

Author: Ehesp

docs/installation.android.md

@@ -0,0 +1,55 @@
+# Android Installation
+
+The simplest way of installing on Android is to use React Native linker:
+
+```
+react-native link react-native-firestack
+```
+
+## Manually
+
+To install `react-native-firestack` manually in our project, we'll need to import the package from `io.fullstack.firestack` in our project's `android/app/src/main/java/com/[app name]/MainApplication.java` and list it as a package for ReactNative in the `getPackages()` function:
+
+```java
+package com.appName;
+// ...
+import io.fullstack.firestack.FirestackPackage;
+// ...
+public class MainApplication extends Application implements ReactApplication {
+    // ...
+
+    @Override
+    protected List<ReactPackage> getPackages() {
+      return Arrays.<ReactPackage>asList(
+          new MainReactPackage(),
+          new FirestackPackage()  // <-- Add this line
+      );
+    }
+  };
+  // ...
+}
+```
+
+We'll also need to list it in our `android/app/build.gradle` file as a dependency that we want React Native to compile. In the `dependencies` listing, add the `compile` line:
+
+```java
+dependencies {
+  compile project(':react-native-firestack')
+}
+```
+
+Add to `AndroidManifest.xml` file
+```diff
+  <activity android:name="com.facebook.react.devsupport.DevSettingsActivity" />
++   <service android:name="io.fullstack.firestack.FirestackMessagingService">
++     <intent-filter>
++       <action android:name="com.google.firebase.MESSAGING_EVENT"/>
++     </intent-filter>
++   </service>
+
++   <service android:name="io.fullstack.firestack.FirestackInstanceIdService" android:exported="false">
++     <intent-filter>
++       <action android:name="com.google.firebase.INSTANCE_ID_EVENT"/>
++     </intent-filter>
++   </service>
+```