Merge pull request 'Update 'webpack.mix.js'' (#67) from dev into master

Reviewed-on: WillaEngine-Project/WillaEngine#67

webpack.mix.js

@@ -44,6 +44,7 @@ require('./modules/wm-product/webpack.mix');
 require('./modules/wm-service/webpack.mix');
 require('./modules/wm-store/webpack.mix');
 require('./modules/wm-warehouse/webpack.mix');
+require('./modules/wm-admin/webpack.mix');
 // require('./modules/wm-web-builder/webpack.mix');
 // require('./modules/wm-reservation/webpack.mix');