[install] Get react-native link working with Android

package.json

@@ -88,8 +88,11 @@
   "rnpm": {
     "android": {
       "buildPatch": "    compile(project(':react-native-firebase')) {\n        transitive = false\n    }\n",
-      "packageImportPath": "import io.invertase.firebase.RNFirebasePackage;\nimport io.invertase.firebase.analytics.RNFirebaseAnalyticsPackage;",
+      "packageImportPath": "import io.invertase.firebase.RNFirebasePackage;",
-      "packageInstance": "new RNFirebasePackage(),\n            new RNFirebaseAnalyticsPackage()"
+      "packageInstance": "new RNFirebasePackage()"
+    },
+    "commands": {
+      "postlink": "node node_modules/react-native-firebase/scripts/rnpm-postlink"
     }
   }
 }

scripts/rnpm-postlink.js

@@ -0,0 +1,26 @@
+const fs = require('fs');
+const path = require('path');
+
+const appBuildGradlePath = path.join('android', 'app', 'build.gradle');
+
+const defaultCompileStatement = "compile project(':react-native-firebase')";
+const requiredCompileStatement = "compile(project(':react-native-firebase')) {\n        transitive = false\n    }";
+
+// android/build.gradle
+// 1) TODO: Add Google Play maven repository
+
+// 2) TODO: Add google-services dependency if required
+
+// android/app/build.gradle
+// 0) Load the file
+let buildGradleContents = fs.readFileSync(appBuildGradlePath, 'utf8');
+
+// 1) Check that react-native-firebase compile statement is the correct format
+buildGradleContents = buildGradleContents.replace(defaultCompileStatement, requiredCompileStatement);
+
+// 2) TODO: Add firebase-core and play-services-base dependencies
+
+// 3) TODO: Add google-services plugin
+
+// 4) Write file
+fs.writeFileSync(appBuildGradlePath, buildGradleContents);