Update readme.md

Author: fernandocode

README.md

@@ -8,6 +8,11 @@ Extended library from [database-builder](https://github.com/fernandocode/databas
 
 ### Step 1: Install npm module
 
+>Required:
+```bash
+ionic cordova plugin add cordova-sqlite-storage
+```
+
 ```bash
 npm install --save ionic-database-builder 
 ```