diff --git a/.gitignore b/.gitignore
index c650246c..c12f3a80 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,2 @@
 /node_modules
-/yarn.lock
 /?.js
diff --git a/.travis.yml b/.travis.yml
index bb8ff352..a161c11e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,7 @@
 language: node_js
 
 node_js:
+  - "4"
   - "6"
   - "8"
   - "10"