Add project description

Author: thespad

readme-vars.yml

@@ -2,6 +2,7 @@
 
 # project information
 project_name: modmanager
+project_description: Modmanager is a centralised tool for downloading and updating docker mods for all your other Linuxserver containers.
 full_custom_readme: |
   {% raw -%}
   [![linuxserver.io](https://raw.githubusercontent.com/linuxserver/docker-templates/master/linuxserver.io/img/linuxserver_medium.png)](https://linuxserver.io)