minetest-mapserver: add comment

sighs

images/minetest-mapserver/minetest-mapserver.sh

@@ -1,5 +1,8 @@
 #!/usr/bin/env bash
 
+# NOTE: mapserver doesn't support the leveldb backend - only sqlite3 or postgresql :-(
+# ....so we'll need to switch to PostgreSQL, but that adds additional complexity..... oh boy
+
 # The architecture - possible values: arm (default), x86, x86_64
 arch="${arch:-arm}";