A lightweight javascript plugin that adds a map list command, and map voting with votes that expire.
Simply download the zip file, pull the folder inside of it out, and put it into your config/mods folder. (A server restart is required to update mods/plugins on your server.)
/maps
will show a list of (custom) maps on the server
/nextmap <map number>
will vote for specified map
votechangesmap <true/false>
will set whether a vote changes the map after. This saves between server restarts
After the first player votes, a 1.5 minute timer is started. After the timer runs out, the votes for each map are counted and the map with the most votes will be selected next.
If there is a tie in votes, it will pick randomly from the winners.