Create emergency branch with hack ride pagination

[john]

1. Add Dan's attached js to the main dispatch page with the map. It does this: "put this in the pages you want to refresh, it checks every 15 seconds and refreshes if it’s been 15 minutes since the page was loaded"

2. Update the conversations method at line L13 of api/v1/ride_zones#conversations to get a limit of 500 conversations, ordered by pickup_date, closest-in-time first.

conversations_api_v1_ride_zone
GET /api/1/ride_zones/:id/conversations(.:format) api/v1/ride_zones#conversations

Have this waiting in a branch on e-day in the unlikely event it's needed.

refresh_rides.js.txt