Add tools target for installing bundler.

Author: cliffano

Makefile

@@ -44,4 +44,7 @@ package: deps
 		stage/aem-aws-stack-provisioner-$(version).tar ./
 	gzip stage/aem-aws-stack-provisioner-$(version).tar
 
-.PHONY: ci clean deps lint package validate
+tools:
+	gem install bundler
+
+.PHONY: ci clean deps lint package validate tools