This assumes that composer is installed on the server and is ready to be executed as the "composer" command
Once you are happy that the project and libs are all tagged and working its time to release the site.
Log into the server via ssh and log into the project user account, from there we can update the site:
$ su - // Login as root
$ su - ems
$ cd public_html/ems
$ ./bin/cmd ug
Be sure that you run any pre install DB updates if you have made any changes that the standard migration cannot handle.
This command will checkout the most recent tag from the repository and rim composer to update the libs, then finally it will run the DB migration commands to update the database if needed.