Ignore coverage folder generated by jest (facebook#541)

ldesplat · feiqitian · commit 5e58c483bdb4 · 2016-10-25T13:58:38.000+08:00
diff --git a/template/gitignore b/template/gitignore
@@ -3,6 +3,9 @@
 # dependencies
 node_modules
 
+# testing
+coverage
+
 # production
 build
 
