Update .gitignore

Change-Id: I9c9f46a596f22e032f82003a31a895b801fcff4b
diff --git a/.gitignore b/.gitignore
index 392afa3..2b36f37 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@
 .RData
 reference
 inst/**/skeleton/skeleton.html
+target/