Fix hot reloading.

[jameshadfield]

Requires running npm install as dependencies have changed

[jameshadfield]

Can someone (@tsibley @emmahodcroft @trvrb) test that this still works for them?

npm run build && npm run server and npm run dev (You'll need to do npm install first)

[tsibley]

The commands work for me as expected (prod server doesn't hot-reload, dev server does).

The dev server does issue this warning:

(node:10421) DeprecationWarning: Tapable.plugin is deprecated. Use new API on `.hooks` instead

which doesn't happen on master.

[jameshadfield]

Great. Thanks.