Tour engagement counter

[jrosindell]

We have a views field on the tour table of our database but it's not being utilised at present from what I can see. We need to update this as a minimum and in future work we could consider giving users the chance to add a * rating and comment for tours after reaching the end.

[lentinj]

I'm fairly sure this was never implemented. But if it were, piping the data to google analytics makes more sense.

Otherwise we turn each tour read into a write, which would mean that only one user could ever be served at a time, as they'd have to wait for their turn to increment the visit counter.

This would also have the advantage of being triggered in Javascript, so more likely someone actually viewing a tour vs. scripts downloading tours.