My first Java project. Probably contains some beginner mistakes and such.
The plugin adds the /vote <day/night> command where players can vote for either day or night time.
At least half of all the online players have to agree. If the vote doesn't pass for 30 seconds it will fail and a new vote can be started.
There cannot be a vote for day and a vote for night at the same time.
Feel free to copy this code and make your own plugin with more customizations.