composer.json

{
  "name": "mycompany/myproject",
  "description": "My project description",
  "type": "project",
  "license": "GPL-2.0+",
  "authors": [
    {
      "name": "",
      "role": ""
    }
  ],
  "repositories": [
    {
      "type": "composer",
      "url": "https://packages.drupal.org/8"
    }
  ],
  "require": {
    "composer/installers": "^1.2",
    "cweagans/composer-patches": "^1.6",
    "drupal-composer/drupal-scaffold": "^2.2",
    "drupal/core": "~8.3"
  },
  "conflict": {
    "drupal/drupal": "*"
  },
  "minimum-stability": "dev",
  "prefer-stable": true,
  "scripts": {
    "drupal-scaffold": "DrupalComposer\\DrupalScaffold\\Plugin::scaffold"
  },
  "extra": {
    "installer-paths": {
      "docroot/core": ["type:drupal-core"],
      "docroot/libraries/{$name}": ["type:drupal-library"],
      "docroot/modules/contrib/{$name}": ["type:drupal-module"],
      "docroot/profiles/contrib/{$name}": ["type:drupal-profile"],
      "docroot/themes/contrib/{$name}": ["type:drupal-theme"],
      "drush/contrib/{$name}": ["type:drupal-drush"]
    }
  }
}