requirements.txt vs composer.json

composer.json

{
    "name": "symfony/framework-standard-edition",
    "description": "The \"Symfony Standard Edition\" distribution",
    "autoload": {
        "psr-0": { "": "src/" }
    },
    "require": {
        "php": ">=5.3.3",
        "symfony/symfony": "2.1.*",
        "doctrine/orm": ">=2.2.3,<2.4-dev",
        "doctrine/doctrine-bundle": "1.0.*",
        "twig/extensions": "1.0.*@dev",
        "symfony/assetic-bundle": "2.1.*",
        "symfony/swiftmailer-bundle": "2.1.*",
        "symfony/monolog-bundle": "2.1.*",
        "sensio/distribution-bundle": "2.1.*",
        "sensio/framework-extra-bundle": "2.1.*",
        "sensio/generator-bundle": "2.1.*",
        "jms/security-extra-bundle": "1.2.*",
        "jms/di-extra-bundle": "1.1.*",
        "kriswallsmith/assetic": "1.1.*@dev",
        "friendsofsymfony/user-bundle": "*",
        "doctrine/data-fixtures" : "dev-master",
        "doctrine/doctrine-fixtures-bundle": "dev-master",
    	"fr3d/ldap-bundle": "1.6.*@dev",
	"winzou/cache-bundle": "dev-master"
    },
    "scripts": {
        "post-install-cmd": [
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::buildBootstrap",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::clearCache",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installAssets",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installRequirementsFile"
        ],
        "post-update-cmd": [
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::buildBootstrap",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::clearCache",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installAssets",
            "Sensio\\Bundle\\DistributionBundle\\Composer\\ScriptHandler::installRequirementsFile"
        ]
    },
    "extra": {
        "symfony-app-dir": "app",
        "symfony-web-dir": "web"
    }
}

requirements.txt

Flask==0.10.1
Jinja2==2.7
MarkupSafe==0.18
Werkzeug==0.9.1
itsdangerous==0.21
wsgiref==0.1.2