Update setup script

Author: gpaddis

setup.sh

@@ -2,8 +2,6 @@
 
 set -e
 
-mkdir -p magento
-
 # Detect OS
 case `uname -s` in
     Darwin) is_macos=yes ;;
@@ -22,11 +20,11 @@ searchAndReplace() {
 }
 
 searchAndReplace "/path/to/magento" "${PWD}/magento" docker-compose.yml
-mv install-magento.sh magento/.
-mv composer.json.magento magento/composer.json
 
 docker-compose down
 docker-compose up -d --build
 
-# Install Magento and setup PHPUnit.
-docker exec -it web-magento1-phpunit bash -c "cd app && bash install-magento.sh"
+# Install Magento and setup PHPUnit, if not already installed.
+if [ ! -f magento/app/etc/local.xml ]; then
+    docker exec -it web-magento1-phpunit bash -c "cd app && bash install-magento.sh"
+fi