backend release workflow

[ascariandrea]

We need to setup also the release workflow for the backend to ensure it keeps deployed continuously.

There are few things to resolve in order to be able to integrate the release process in our CI:

• strong tests in place that prevent the introduction of "bugged" code
• having mostly of the codebase rewritten with typescript
• a db migration strategy
• define how the code gets updated and deployed in the server (I suggest docker :) )