Hi, the build system is quite flexible. It's used to build all the open source apps currently available in the app store.

That DB keyword basically allows you to roll out a linked database container for your app if required. Only Mysql and Postgresql is currently supported. These are Mysql and Postgresql instances that can be used for this.

A lot of apps require databases and instead of configuring it manually this allows some degree of automation so a linked database container can be easily deployed if required.