add key components

Author: Smart-City-Muenster

docs/standard/schema.core.rst

@@ -64,6 +64,18 @@ See :ref:`forks-and-variants` for a complete description of what
 is a software variant and how to handle forked software as a parser or
 an author.
 
+Key ``components``
+~~~~~~~~~~~
+
+-  Type: array of strings (URLs)
+-  Presence: optional
+
+Some software projects are organized in more than one repository.
+In addition to the key ``url``, this key gives you an option to specify
+more than one URL to further relevant repositories. If you use the key,
+you need to specify the URL in the same way as is required for the key ``url``.
+You can specify more than URL.
+
 Key ``landingURL``
 ~~~~~~~~~~~~~~~~~~