You don't need to build Pleroma yourself. Check out https://git.pleroma.social/pleroma/pleroma-fe/wikis/dual-boot-with-qvitter to see how to run Pleroma and Qvitter at the same time.
For detailed explanation on how things work, checkout the [guide](http://vuejs-templates.github.io/webpack/) and [docs for vue-loader](http://vuejs.github.io/vue-loader).