Throw this in .git/hooks/commit-msg and chmod +x it.

commit-msg

#!/usr/local/bin/node

/* jshint node:true */

// This hook ensures the commit message includes [ci skip] or [ci run]

var fs = require('fs'),
    spawn = require('child_process').spawn,
    args = process.argv.slice(2),
    filePath = args[0],
    exists = fs.existsSync(filePath),
    contents = exists && fs.readFileSync(filePath, "utf8"),
    spawnOptions = {detached: true, stdio: 'ignore'},
    say;

if (!contents) {
  console.log('commit-msg hook is confused.');
  process.exit(1);
}

if (!/\[ci (skip|run)\]/.test(contents)) {
  console.log("No [ci skip] or [ci run] found:\n\n" + contents);
  say = spawn('say', ['-r170', '-vagnes', 'compuwer says no'], spawnOptions);
  process.exit(1);
}
else {
  say = spawn('say', ['BOOM!!!'], spawnOptions);
  process.exit(0);
}