added to remote repo

frontend/node_modules/postcss-import/lib/join-layer.js

@@ -0,0 +1,9 @@
+"use strict"
+
+module.exports = function (parentLayer, childLayer) {
+  if (!parentLayer.length && childLayer.length) return childLayer
+  if (parentLayer.length && !childLayer.length) return parentLayer
+  if (!parentLayer.length && !childLayer.length) return []
+
+  return parentLayer.concat(childLayer)
+}