Added Android SDK conflict issues

README.md

@@ -64,6 +64,36 @@ If you're using this template: [vue-cli-template](https://github.com/nativescrip
 
 And also, `require` the plugin before Vue.start runs (probably in `main.js`), but run `firebase.init()` afterwards (although it may work before). You could wrap it in a timeout to make sure.
 
+### Android SDK conflicts
+Some users experienced build conflicts after installing the plugin. SDK version issues may prevent your app from building and installing on a physical Android device. Here is what you should do.
+
+After starting your NativeScript project, adding and configuring the plugin, registering your app on Firebase Console and adding `google-services.json` to your `App_Resources/Android` directory, try `tns run android` on your device. Gradle may fail and produce various error messages similar to this:
+
+`.../values-v26.xml:9:5-12:13: AAPT: error: resource android:attr/colorError not found.`
+
+This is caused by an Android SDK incompatibility. You can fix it by modifying `platforms/android/app/build.gradle`. Change this part:
+
+```
+defaultConfig {
+    minSdkVersion 17
+    targetSdkVersion computeTargetSdkVersion()
+    ...
+}
+```
+
+to this:
+
+```   
+defaultConfig {
+    minSdkVersion 17
+    targetSdkVersion 26
+    multiDexEnabled true
+    ...
+}
+```
+
+This forces Gradle to use API 26. Lower versions miss a few components required for the build. Of course you can set it even higher if you need a newer API. Multidex is also needed for a successful build. Don't forget to set this again if you update or change the project's Android platform.
+
 ### iOS (Cocoapods)
 The Firebase iOS SDK is installed via Cocoapods, so run `pod repo update` from the command prompt (in any folder) to ensure you have the latest spec.