Merge pull request #18 from segmentio/firebase-kotlin

DOC-322 Setting up Firebase with Kotlin

Author: stayseesong

src/connections/destinations/catalog/firebase/index.md

@@ -114,6 +114,42 @@ If you use Segment's React Native source library, you must explicitly bundle the
 
 <!-- LR Mar 2021: We didn't use the react-dest include here because Firebase needs the extra build.gradle step.-->
 
+## Setting up Firebase with Analytics-Kotlin
+If you're using the [Analytics-Kotlin library](/docs/connections/sources/catalog/libraries/mobile/kotlin-android), follow these steps to set up Firebase with Analytics-Kotlin:
+1. In your top-level `build.gradle` file add these lines:
+    ```kotlin  
+    buildscript {
+        ...
+        repositories {
+            google()
+        }
+        dependencies {
+            ...
+            classpath 'com.google.gms:google-services:4.3.5'
+        }
+    }
+    ```    
+2. In your app-module `build.gradle` file add these lines:
+    ```kotlin
+    ...
+    plugins {
+        id 'com.google.gms.google-services'
+    }
+
+    dependencies {
+        ...
+        implementation platform('com.google.firebase:firebase-bom:28.2.1')
+        implementation 'com.google.firebase:firebase-analytics-ktx'
+    }
+    ```
+3. Copy the [FirebaseDestination.kt](https://github.com/segmentio/analytics-kotlin/blob/main/samples/kotlin-android-app-destinations/src/main/java/com/segment/analytics/destinations/plugins/FirebaseDestination.kt) file into your project's codebase.
+4. Copy your `google-service.json` file to your app-module.
+5. Go to your project's codebase and add these lines where you intialize the analytics client:
+    ```kotlin
+    val Firebase = FirebaseDestination()
+    analytics.add(Firebase)
+    ```
+
 ## Identify
 
 When you call `identify` Segment will map to the corresponding Firebase Analytics calls: