update Build Arguments section in build.sh

build.sh

@@ -11,12 +11,13 @@ echo "Building GeoServer using the specified version "
 sed -i "s/${OLD_MAJOR}.${OLD_MINOR}.${OLD_BUGFIX}/${MAJOR}.${MINOR}.${BUGFIX}/g" Dockerfile
 docker build --build-arg GS_VERSION=${MAJOR}.${MINOR}.${BUGFIX} -t kartoza/geoserver:${MAJOR}.${MINOR}.${BUGFIX} .
 
-# Build Arguments - The change the defaults when building the image
+# Build Arguments - To change the defaults when building the image
 #need to specify a different value.
 ```
 --build-arg ORACLE_JDK=true
 --build-arg COMMUNITY_MODULES=true
 --build-arg TOMCAT_EXTRAS=false
+--build-arg WAR_URL=http://downloads.sourceforge.net/project/geoserver/GeoServer/<GS_VERSION>/geoserver-<GS_VERSION>-war.zip
 ```