Composer package not found in any version

I am trying to create a custom vendor package but have not yet put the package on packagist. According to the docs, the package can be loaded from git (vcs) instead of packagist: https://getcomposer.org/doc/05-repositories.md#loading-a-package-from-a-vcs-repository

The yii2 project (although don't think framework matters) I have created package inside vendor folder:

foundationize/yii2-foundation (folder structure is as above, I have quadruple-checked).

My root public_html/composer.json has following entries:

"minimum-stability": "dev",
    "require": {
        "php": ">=5.4.0",
        "yiisoft/yii2": ">=2.0.5",
        "yiisoft/yii2-swiftmailer": "*",
        "foundationize/yii2-foundation": "dev-master" 
    },

My package composer file, vendor/foundationize/yii2-foundation/composer.json looks like:

{
    "name": "foundationize/yii2-foundation",
    "description": "The Foundation extension for the Yii2 framework",
    "keywords": ["yii2", "foundation"],
    "type": "yii2-extension",
    "license": "BSD-3-Clause",
    "support": {
        "issues": "https://github.com/foundationize/yii2-foundation/issues",
        "wiki": "https://github.com/foundationize/yii2-foundation/wiki",
        "source": "https://github.com/foundationize/yii2-foundation.git"
    },
    "authors": [
        {
            "name": "gvanto",
            "email": "gvanto@hotmail.com",
            "homepage": "http://foundationize.com"
        }
    ],
    "require": {
        "yiisoft/yii2": "*"
    },
    "autoload": {
        "psr-4": {
            "foundationize\\foundation\\": ""
        }
    },
    "repositories": [
        {
            "packagist": false,
            "type": "vcs",
            "url": "https://github.com/foundationize/yii2-foundation.git"           
        }
    ]       
}

When I run composer install (or update), I keep getting error below:

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

Problem 1 - The requested package foundationize/yii2-foundation could not be found in any version, there may be a typo in the package name.

Potential causes:

• A typo in the package name
• The package is not available in a stable-enough version according to your minimum-stability setting see https://groups.google.com/d/topic/composer-dev/_g3ASeIFlrc/discussion for more details.

Read https://getcomposer.org/doc/articles/troubleshooting.md for further common problems.

I have googled it high and low, read the docs can't seem to get it to work (always the same error, which I actually think would be more useful if it said either the package was not found OR the incorrect package version was found).

You have to add the repositories entry to your root composer.json file. Otherwise, Composer does not know where to search for your package.