node-mysql2 works with uglifyjs

[William Huang]

    new webpack.optimize.UglifyJsPlugin({
      compress: {
        unused: true,
        dead_code: true,
        warnings: false,
        drop_debugger: true,
      },
      comments: false,
      mangle: false,
    }),

mangle:false

the above setting will allow node-mysql2 to work, not really an issue per say but just a discovery for modules that have problems,