For my mobile app i would prefer to use ruby on rails as a programming language as i have some experience with this language and it is very easy to learn. setting up the back-end is very easy and it allows you to add your own styling by adding bootstrap and your own custom CSS. It offers a mechanism that encourages language economy to reduce written text, preserve time-oriented efficacy, and minimally impede creation from start to finish.

For the user interface i would use React. It is open-source JavaScript Library. Without reloading the tab, React enables massive web apps to be developed that can alter details.The primary objective is to be efficient, flexible, and simple.

For build processes i would prefer Babel. i have used it couple of times before and it is very easy to learn and work with. It Transforms the syntax and source code. It Polyfill features that are missing in your target environment.And it is easy to install.

If you are working on ruby on rails it provides you the opportunity to any database PostgreSQL, MySQL and SQLite.But when managing large data sets, complex requests, and read-write operations, it is simpler. So i would choose PostgreSQL.