Fixed issue with sourcemaps

* Rather than creating a separate sourcemap file, instead, use the eval option. * Thus, no need for moving the created sourcemap file.

Author: justin808

webpack/webpack.rails.config.js

@@ -37,21 +37,10 @@ module.exports = {
 var devBuild = (typeof process.env["BUILDPACK_URL"]) === "undefined";
 if (devBuild) {
  console.log("Webpack dev build for rails");
- module.exports.devtool = "source-map";
+ module.exports.devtool = "eval-source-map";
  module.exports.module.loaders.push(
  { test: require.resolve("react"), loader: "expose?React" }
  );
- module.exports.plugins = [
- function () {
- this.plugin("emit", function (compilation, callback) {
- // CRITICAL: This must be a relative path from the railsJsAssetsDir (where gen file goes)
- var asset = compilation.assets[railsBundleMapFile];
- compilation.assets[railsBundleMapRelativePath] = asset;
- delete compilation.assets[railsBundleMapFile];
- callback();
- });
- }
- ];
 } else {
  console.log("Webpack production build for rails");
 }