Add Library Path

I've been searching all over for this. I'm trying to run the Calibre server in an Alpine Docker but it keeps giving me the following error:

/opt/calibre/bin/calibre-server: error while loading shared libraries: libcalibre-launcher.so: cannot open shared object file: No such file or directory

I know I need to add "/opt/calibre/lib" to the library search but how do I do that in Alpine? I see the /etc/ld.so.cache file but I don't see a way to add a path to it.