updates README.adoc

curl and jar, rather than separate unzip
diff --git a/README.adoc b/README.adoc
index ba4901d..e68a9d0 100644
--- a/README.adoc
+++ b/README.adoc
@@ -24,8 +24,7 @@
 REPO=isis-app-helloworld
 BRANCH=master
 
-curl "https://codeload.github.com/apache/$REPO/zip/$BRANCH" > $REPO-$BRANCH.zip
-unzip $REPO-$BRANCH.zip
+curl "https://codeload.github.com/apache/$REPO/zip/$BRANCH" | jar xv
 mv $REPO-$BRANCH $REPO
 cd $REPO
 ----