explanatory comment

lib/pipeline/webpack.config.js

@@ -52,6 +52,10 @@ try {
 const entry = Object.keys(embarkAssets)
   .filter(key => key.match(/\.js?$/))
   .reduce((obj, key) => {
+    // webpack entry paths should start with './' if they're relative to the
+    // webpack context; embark.json "app" keys correspond to lists of .js
+    // source paths relative to the top-level dapp dir and may be missing the
+    // leading './'
     obj[key] = embarkAssets[key]
       .map(file => {
         let file_path = file.path;