LGTM button for pull requests.

gistfile1.js

// ==UserScript==
// @name        LGTM Button
// @namespace   lgtm.github.com
// @description Add a LGTM button to pull requests.
// @include     https://github.com/Skookum/*/pull/*
// @version     1
// ==/UserScript==
var lgtmButton = document.createElement('button'),
    buttonCont = document.querySelector('button[name="comment_and_close"]').parentNode,
    commentBtn = buttonCont.querySelector('button:last-child');

lgtmButton.innerHTML = "LGTM";
lgtmButton.setAttribute('class', 'button primary');
lgtmButton.onclick = function (e) {
  buttonCont.parentNode.querySelector('textarea:last-of-type').innerHTML = "LGTM";
  window.location.reload();
};

buttonCont.appendChild(lgtmButton);