Make a war file from multi module vaadin maven springboot project

Hi everybody.

We are using a project (mycollab) that is multi module and made of Vaadin 7.7.13 , maven 3+ and spring boot 2.0.3 that runs on a embedded jetty. We need to make a war file from it and deploy it to tomcat. All modules together make a project.

Project structure is :

-parent app