Auto Synchronise local mySQL changes with server mySQL

Imagine the scenario - 20 developers all working on the same mysql database file - each one on their own local machine. That is, they grab the server mySQL sql install it locally (say on phpMyAdmin) then run XAMMP to develop PHP code and make database modifications. Throughout the day they merrily add tables, change schemas, add data - never thinking much the the changes the other 19 developers are doing. Now the fun part. The 20 developers go home and the database admin gets 20 SQL files and has to merge them into one "no-data-has-been-lost" sql file. The above is a purely fictitious story but it gives you a good idea of what happens when even 2 people work locally on the same mySQL code and then try to merge their changes. 20 is a great number because you cannot do it manually. WHAT I NEED: I need someone to provide code (or access to a tool) to automate this process so that any SQL change made by (say) 20 developers could easily be merged into 1 SQL file and uploaded to the server with no loss of data. The server is PHP/mySQL/github is used. Local machine is XAMMP. The script would ideally have GIT hooks so that when github is updated with code the mySQL merger would trigger and the code and the mysql would stay in sequence. I have a huge amount of work in server admin coming up so if you can show me your skills this could be the start of a great long term relationship.