Improved position editing and friday fixes

Some small improvements and fixes out today. Positions are now much easier to modify: you can seamlessly add and remove skills without waiting for page reloads.

Screenshot 2019-05-10 at 16.11.24.png

We've also improved the experience of adding users to positions whereever you see the "+" sign.

Screenshot 2019-05-10 at 16.17.45.png

Finally there are several small tweaks and fixes around inviting team members and logging in with your Google account.