Running out of memory when running composer install

Question

I've inherited a laravel 5.1 project, but when I run composer install on a new install of the project, I run out of memory before all of the dependancies could be installed. I'm fairly new to composer, but looking at docs, it appears as though the composer.json file is set up correctly. Here is a copy of the json file. From what I've been told, the project used to perform a composer install/update without issue, but slowly started taking more and more time until it eventually failed due to lack of memory. PHP is currently set at -1 for unlimited memory. I originally thought maybe there was some weird dependancy stuff happening in the required packages, but I don't see anything in the private packages being included at the top of the composer.json. If you want to see anything from those, let me know and I can add them. The actual error I'm getting is:

Uncaught exception 'ErrorException' with message 'proc_open(): fork failed - Cannot allocate memory' in phar:///usr/local/bin/composer/vendor/symfony/console/Application.php:954
Stack trace:
#0 [internal function]: Composer\Util\ErrorHandler::handle(2, 'proc_open(): fo...', 'phar:///usr/loc...', 954, Array)
#1 phar:///usr/local/bin/composer/vendor/symfony/console/Application.php(954): proc_open('stty -a | grep ...', Array, NULL, NULL, NULL, Array)
#2 phar:///usr/local/bin/composer/vendor/symfony/console/Application.php(754): Symfony\Component\Console\Application->getSttyColumns()
#3 phar:///usr/local/bin/composer/vendor/symfony/console/Application.php(715): Symfony\Component\Console\Application->getTerminalDimensions()
#4 phar:///usr/local/bin/composer/vendor/symfony/console/Application.php(648): Symfony\Component\Console\Application->getTerminalWidth()
#5 phar:///usr/local/bin/composer/vendor/symfony/console/Application.php(130): Symfony\Component\Console\Application->renderException(Object(ErrorException),  in phar:///usr/local/bin/composer/vendor/symfony/console/Application.php on line 954

Here is a copy of what is in my composer.json

{
    "name": "activewebsite/broker-v2-base",
    "description": "Enterprise V2",
    "license": "proprietary",
    "repositories": [
        {
            "type": "vcs",
            "url": "https://github.com/activewebsite/requirejs"
        },
        {
            "type": "vcs",
            "url": "https://github.com/activewebsite/fancybox"
        },
        {
            "type": "vcs",
            "url": "https://github.com/activewebsite/typeahead.js"
        },
        {
            "type": "vcs",
            "url": "https://github.com/activewebsite/Sortable"
        },
        {
            "type": "vcs",
            "url": "https://github.com/activewebsite/ckeditor"
        }
    ],
    "require": {
        "laravel/framework": "5.1.*",
        "activewebsite/requirejs": "~1.0.0",
        "activewebsite/fancybox": "~1.0.0",
        "activewebsite/typeahead": "~1.0.0",
        "activewebsite/Sortable": "~1.0.0",
        "activewebsite/ckeditor": "~1.0.0",
        "aloha/twilio": "3.0.0",
        "barryvdh/laravel-debugbar": "2.0.*@dev",
        "cartalyst/sentinel": "2.0.*",
        "components/bootstrap": "~3.3.5",
        "components/font-awesome": "~4.3.0",
        "components/jquery": "~1.11.3",
        "components/modernizr": "~2.8.3",
        "doctrine/dbal": "~2.5",
        "eonasdan/bootstrap-datetimepicker": "~4.17",
        "fintech-fab/laravel-queue-rabbitmq": "~5.1.0",
        "ixudra/curl": "6.*",
        "laravelcollective/html": "~5.0",
        "shift31/laravel-elasticsearch": "1.3.4",
        "predis/predis": "~1.0",
        "mews/purifier": "~2.0"
    },
    "require-dev": {
        "fzaninotto/faker": "1.5.*@dev",
        "mockery/mockery": "~0.9",
        "phpunit/phpunit": "~4.5",
        "phpspec/phpspec": "~2.1"
    },
    "autoload": {
        "classmap": [
            "database/seeds"
        ],
        "psr-4": {
            "Booj\\": "app/"
        }
    },
    "autoload-dev": {
        "classmap": [
            "tests/TestCase.php",
            "tests/EnterpriseTestCase.php",
            "tests/Models/Messages/MessageListeners/MessageMatchers/BaseMessageMatcherTest.php",
            "tests/Models/Processors/Identifiers/AgentIdentifiers/BaseAgentIdentifierTest.php",
            "tests/Models/Reactor/ReactorEventRuleActions/BaseReactorRuleActionExecutorTest.php",
            "tests/Models/Templates/TemplatePopulators/TemplateInstanceBasedTest.php"
        ]
    },
    "scripts": {
        "post-install-cmd": [],
        "post-update-cmd": []
    },
    "config": {
        "preferred-install": "dist",
        "secure-http": false
    },
    "minimum-stability": "dev",
    "prefer-stable": true
}

Any tips or advice would be appreciated.