Use setting instead of hard-coding port

services/track-changes/config/settings.defaults.coffee

@@ -14,7 +14,7 @@ module.exports =
 		docstore:
 			url: "http://#{process.env["DOCSTORE_HOST"] or "localhost"}:3016"
 		web:
-			url: "http://#{process.env["WEB_HOST"] or "localhost"}:3000"
+			url: "http://#{process.env["WEB_HOST"] or "localhost"}:#{process.env['WEB_PORT'] or 3000}"
 			user: "sharelatex"
 			pass: "password"
 	redis: