Sets Bitbucket, Github, Gist or (whatever you add) source code view indentation to something sensible

sourceview-indentation-fix.js

// ==UserScript==
// @name         Source View Indentation Fix
// @namespace    http://davestewart.io
// @version      1.0
// @description  Sets Bitbucket, Github, Gist or (whatever you add) source code view indentation to something sensible
// @author       Dave Stewart
// @grant        none
// @match        https://bitbucket.org/*
// @match        https://gist.github.com
// @match        https://gist.github.com/*
// @match        https://github.com/*
// ==/UserScript==

// -----------------------------------------------------------------------------------------------------------
// user preferences

	// tab sizes
		var sizes = 
		{
			// add / modify language extensions here...
			default	:4,
			html	:4,
			js		:4,
			rb		:2
		};
	
	// selectors

		var selectors = 
		{
			// add / modifiy selector templates here...
			general:
			[
				'pre, pre *',                                       // preformatted tags & content
				'.code pre',                                        // bitbucket
				'.line'                                             // gist            
			],
			diffs:
			[
				'div[class*="{lang}-"] td',                         // github
				'section[data-filename$=".{lang}"] pre.source'      // bitbucket
			],
			files:
			[
				'div.{lang}-blob-data div.line',                    // gist
				'td.{lang}-file-line',                              // github
				'#editor-container[data-source-url$="{lang}"] pre'  // bitbucket
			]
			
		};


// -----------------------------------------------------------------------------------------------------------
// code

	// setup

		function addStyle(selector, lang, size)
		{
			selector = selector.replace('{lang}', lang);
			styles += selector + '{ tab-size: ' +size+ '; }\n';
		}
	
		var styles = '';
	
	// build styles
	
		// loop over types
		for(var type in selectors)
		{
			// add heading
			styles += '\n/* ' +type+ ' */\n\n';
			
			// loop over rules
			for(var i = 0; i < selectors[type].length; i++)
			{
				var selector = selectors[type][i];
				
				// if no {lang} variable is found in the selector, just add the style once
				if(selector.indexOf('{lang}') == -1)
				{
					addStyle(selector, null, sizes.default);
				}
				
				// otherwise, create a new rule for each language
				else
				{
					for(var lang in sizes)
					{
						if(lang !== 'default')
						{
							addStyle(selector, lang, sizes[lang]);
						}
					}
				}				
	
			}
			
		}
	
	// add styles to  page
		console.log('Code view indentation modified by Tampermonkey script "Source View Indentation Fix"');
		$('head').append('<style>' +styles+ '</style>');

Hm, not working for me :(