Allow .jsx to not require its extension

This is in part because PhpStorm assumes this - autocompletes without the extension.
And also, it IS a .js file... so I think it's a good idea

Author: weaverryan

lib/config-generator.js

@@ -63,6 +63,10 @@ class ConfigGenerator {
 
         config.stats = this.buildStatsConfig();
 
+        config.resolve = {
+            extensions: ['.js', '.jsx']
+        };
+
         return config;
     }