Add debian support.

manifests/server.pp

@@ -126,8 +126,13 @@ class mpd::server (
         require => Yumrepo['rpm-fusion'],
       }
     }
+    'Debian': {
+      package { ['mpd']:
+        ensure => installed,
+      }
+    }
     default: {
-      fail('Currently only works on CentOS')
+      fail('OS Not supported')
     }
   }
 }