D8:Adding a new module to a build.

new_module.md

• If this is a profile you will need to add the module to the PROFILE.info.yml file.
• To ensure the module is enabled add it to sites/default/config/core.extension.yml
• Now to actually add the module to the codebase:
• If using a make file find the PROJECT.make file and add an entry there as well, e.g.,:

 flag:
  download:
    # 2016-7-20
    branch: "8.x-4.x"
    revision: eceaa7d

• If using composer:

  "require": {
  "drupal/flag": "8.4.x-dev#eceaa7d",
  }