Bukkit

MySQL:
  username:USERNAME HERE
  //Insert your username here

  password: PASSWORD HERE
  //Insert your password here

  url: jdbc:mysql://127.0.0.1:3306/database
   //127.0.0.1 is your local host. 
   //If your MySQL is on your localhost. 
   //You can leave this. If it is not, obviously change it.
   //example: //***.***.*** or sitename.com
   //MySQL defaults port is 3306
   //If it's on another port, obviously change it.
   //Make sure the /database is your actual database name!

config:
  generateDefClassesYML: true  
  //SET THE THIS TO FALSE, if you are done making your classes. 
  //It does exactly what it says. It will over ride some changes that you have 
  //made to your classes.yml. So, it's best to just set that to false before
  //it makes you want to pull your hair out.

  maxLevel: 30 
  //Max level you plan to go to.