title: How can I resolve "Your requirements could not be resolved to an installable set of packages" error?
body: <p>When I run <code>composer update</code> I receive some wired output.</p>
  
  <p><img src="https://i.stack.imgur.com/hVM3L.png" alt="enter image description here"></p>
  
  <p>Here is my composer.json look like.</p>
  
  <pre><code>{
      "name": "laravel/laravel",
      "description": "The Laravel Framework.", "keywords": ["framework", "laravel"],
      "license": "MIT",
      "repositories": [{
          "type": "vcs",
          "url": "https://github.com/Zizaco/ardent.git"
      }],
      "require-dev": {
          "phpunit/phpunit": "4.3.*"
      },
      "require": {
          "laravel/framework": "4.2.*", 
          "laravelbook/ardent": "dev-master as 2.4.0", 
          "zizaco/entrust": "dev-master", 
          "sebklaus/profiler": "dev-master", 
          "doctrine/dbal": "dev-master"
      },
      "autoload": {
          "classmap": [
              "app/commands",
              "app/controllers",
              "app/models",
              "app/database/migrations", "app/database/seeds", "app/tests",
              "app/libraries"
          ]
      },
      "scripts": {
          "post-install-cmd": [
              "php artisan clear-compiled", 
              "php artisan optimize"
          ],
          "post-update-cmd": [
              "php artisan clear-compiled", 
              "php artisan optimize"
          ],
          "post-create-project-cmd": [
              "php artisan key:generate"
          ]
      },
      "config": {
          "preferred-install": "dist"
      },
      "minimum-stability": "stable"
  }
  </code></pre>
  
  <p>How do I fix that ? </p>