Sample of replacing a repo in composer with your own fork

composer.json

{
	"repositories":[
	    {
	        "type":"git",
	        "url":"https://github.com/natefanaro/Imagine"
	    }
	    {
	        "type":"git",
	        "url":"https://github.com/natefanaro/memegenerator"
	    }
	],
	"require": {
		"noiselabs/configparser": "dev-master",
		"symfony/class-loader": "dev-master",
		"imagine/imagine": "dev-master",
		"piotrbelina/memegenerator": "dev-master",
		"guzzle/guzzle": "3.7.*@dev",
		"rezzza/flickr": "1.0.*@dev"
	}
}