// App secrets are ordered in a tree structure:
$secrets == [
    'MYSQL' => [
        'PASSWORD' => "{{mysql-password}}",
        'USER'     => "{{mysql-user}}",
        'DATABASE' => "{{mysql-database}}",
        'HOST'     => "{{mysql-host}}",
        'PORT'     => "{{mysql-port}}",
    ],
    'CUSTOM' => [
        'YOUR_CUSTOM_SECRET'    => "{{YOUR_CUSTOM_SECRET}}",
        'yourOtherCustomSecret' => "{{yourOtherCustomSecret}}"
    ]
];