Accept arrays of messages to send to client

services/real-time/app/coffee/HttpApiController.coffee

@@ -4,5 +4,9 @@ logger = require "logger-sharelatex"
 module.exports = HttpApiController =
 	sendMessage: (req, res, next) ->
 		logger.log {message: req.params.message}, "sending message"
-		WebsocketLoadBalancer.emitToRoom req.params.project_id, req.params.message, req.body
+		if Array.isArray(req.body)
+			for payload in req.body
+				WebsocketLoadBalancer.emitToRoom req.params.project_id, req.params.message, payload
+		else
+			WebsocketLoadBalancer.emitToRoom req.params.project_id, req.params.message, req.body
 		res.send 204 # No content