update ulogger so it dosen't recreate everytime

modules/nixos/ulogger.nix

@@ -258,10 +258,10 @@ in
         echo "Setting up ulogger-server files in ${cfg.dataDir} ..."
         cd "${cfg.dataDir}"
 
-        cp -R ${cfg.package}/* ./
-        cp ${configFile}/config.php ./
-
         if [ ! -f installed ]; then
+          cp -R ${cfg.package}/* ./
+          cp ${configFile}/config.php ./
+
           echo "Install file not found, installing ..."
           psql -U ulogger < ${cfg.package}/scripts/ulogger.pgsql
           psql -d ulogger -c "INSERT INTO users (login, password, admin) VALUES ('$ULOGGER_ADMIN_USER', '$ULOGGER_ADMIN_PASSWORD', TRUE)"