Customised url for activities#335

We would love to be able to customise the url for activities, so we can promote multiple dates of events at a time, easily, on social media, with one memorable link.

for example:

https://dandelion.events/activities/5e413a4d6a864b0004af0254

to be

https://dandelion.events/activities/shroomshops
or even better
https://dandelion.events/shroomshops