Dynamically list the church's groups

[achan]

Currently, the groups at the end of the homepage are hard-coded. Let's load them dynamically.

• Update mirage to have more (random) groups with server.create("group"): https://github.com/openmcac/mcac-js/blob/master/mirage/scenarios/default.js#L3
• Fetch all groups from the server: Hint
• Iterate through them to create each group