Doesn’t update automatically after changing REV variable

[bouk]

Great job on the project! It works nicely.

There’s just one issue I’ve walked into: if you keep using the same location for the data and restart the container after changing the REV variable, the unit script won’t update the jar automatically. Instead you have to delete the server jar manually. It would be great if the init script compared the version of the jar, or did maybe put the version into the file name of the jar so it knew to install after changing the revision.

[mathuin]

I have a modified version of spigot_init.sh which addresses this issue and a few others.

• If REV is set to a particular version number, say '1.13', the script checks to see if spigot-1.13.jar exists -- if not, it is created.
• If REV is unset, or is set to 'latest', the jar is rebuilt every time.

There are some other changes, too, like creating a non-root user and abstracting out the URLs to script variables. I can make a pull request if that's desired.