function bash to update a symfony 1.4 project

_update_project

function _update_project {
    if [ -z "$1"  ] || [ -z "$2" ]; then
        echo 'You have to call this method with 2 parameters, the git tag/branch name and the environment (prod, dev, ...)'
        return
    fi

    git fetch -a
    git checkout $1
    git pull
    composer install
    php symfony doc:mig --env=$2
    chown www-data:www-data ./ -R
}