Install a WordPress stack via Composer that includes a few plugins and the Roots.io theme.

composer.json

{
    "name"        : "hereswhatidid/install-wordpress-test",
    "description" : "Test project for WordPress stack via Composer",
    "authors"     : [
    {
        "name"    : "Gabe Shackle",
        "email"   : "gabe@hereswhatidid.com",
        "homepage": "http://www.hereswhatidid.com/"
    }
    ],
    "type"        : "project",
    "repositories": [
        {
            "type": "composer",
            "url" : "http://wpackagist.org"
        },
        {
            "type": "composer",
            "url" : "http://rarst.net"
        },
        {
          "type": "package",
          "package": {
            "name": "roots",
            "type": "wordpress-theme",
            "version": "6.5",
            "dist": {
              "type": "zip",
              "url": "https://github.com/roots/roots/zipball/master"
            }
          }
        }
    ],
    "config"      : {
        "vendor-dir": "content/vendor"
    },
    "require"     : {
        "rarst/wordpress"                       :   ">=3.6",
        "roots"                                 :   ">=6.5",
        "wpackagist/advanced-custom-fields"     :   "~4.2",
        "wpackagist/theme-check"                :   "*",
        "wpackagist/custom-post-type-ui"        :   "~0.8"
    },
    "extra": {
        "wordpress-install-dir": "wp",
        "installer-paths": {
            "content/plugins/{$name}/": ["type:wordpress-plugin"],
            "content/themes/{$name}/": ["type:wordpress-theme"]
        }
    }
}