Laravel deployement Your requirements could not be resolved to an installable set of packages

Question

When I am trying to deploy my laravel project and do a php composer.phar install I get this annoying error. I pulled in my project via git with a git clone. And when I surf to my domainname I would like to see my app obviously :). I've installed a correct version of apache, mysql and php. Everything is up and running.

EDIT How do I install gd & dom?

when I do yum install php-gd I get this error: Error: php56w-common conflicts with php-common-5.4.16-36.el7_1.x86_64

Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
Your requirements could not be resolved to an installable set of packages.

Problem 1
- Installation request for brianmcdo/image-palette dev-master -> satisfiable by brianmcdo/image-palette[dev-master].
- brianmcdo/image-palette dev-master requires ext-gd * -> the requested PHP extension gd is missing from your system.
Problem 2
- Installation request for phpunit/phpunit 4.8.18 -> satisfiable by phpunit/phpunit[4.8.18].
- phpunit/phpunit 4.8.18 requires ext-dom * -> the requested PHP extension dom is missing from your system.

My composer.json

"name": "laravel/laravel",
"description": "The Laravel Framework.",
"keywords": ["framework", "laravel"],
"license": "MIT",
"type": "project",
"require": {
    "php": ">=5.5.9",
    "laravel/framework": "5.1.*",
    "creativeorange/gravatar": "~1.0",
    "illuminate/html": "^5.0",
    "laravelcollective/html": "^5.1",
    "intervention/image": "^2.3",
    "brianmcdo/image-palette": "dev-master",
    "weblee/mandrill": "dev-master",
    "behat/behat": "^3.0",
    "behat/mink": "^1.6",
    "behat/mink-extension": "^2.0",
    "behat/mink-selenium2-driver": "1.2.0"
},
"require-dev": {
    "fzaninotto/faker": "~1.4",
    "mockery/mockery": "0.9.*",
    "phpunit/phpunit": "~4.0",
    "phpspec/phpspec": "~2.1"
},
"autoload": {
    "classmap": [
        "database"
    ],
    "psr-4": {
        "App\\": "app/"
    }
},
"autoload-dev": {
    "classmap": [
        "tests/TestCase.php"
    ]
},
"scripts": {
    "post-install-cmd": [
        "php artisan clear-compiled",
        "php artisan optimize"
    ],
    "pre-update-cmd": [
        "php artisan clear-compiled"
    ],
    "post-update-cmd": [
        "php artisan optimize"
    ],
    "post-root-package-install": [
        "php -r \"copy('.env.example', '.env');\""
    ],
    "post-create-project-cmd": [
        "php artisan key:generate"
    ]
},
"config": {
    "preferred-install": "dist"
}

}

Anyone can help me out! many thanks!

Answer 1

First run these two commands to install RPMs for PHP 5.5:

rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
rpm -Uvh https://mirror.webtatic.com/yum/el7/webtatic-release.rpm

Then run:

yum install php-gd

for more details, check this thread.