use development mode and devtool option to improve debugging experience

Author: archmoj

devtools/test_dashboard/server.js

@@ -9,8 +9,8 @@ var minimist = require('minimist');
 var constants = require('../../tasks/util/constants');
 var config = require('../../webpack.config.js');
 config.optimization = { minimize: false };
-// If interested in development mode
-// config.mode = 'development';
+config.mode = 'development';
+config.devtool = 'eval';
 
 var args = minimist(process.argv.slice(2), {});
 var PORT = args.port || 3000;