ignore *.class with .gitignore (#2448)

diff --git a/.gitignore b/.gitignore
index 437ce4c..3cad311 100644
--- a/.gitignore
+++ b/.gitignore
@@ -41,6 +41,7 @@
 
 # IntelliJ
 .idea
+*.class
 
 # Ansible
 ansible/environments/docker-machine/hosts