Add README.rst to security-doc repo

The security-doc repository has very useful documentation needed for the
OpenStack Security Guide. But, unlike the openstack-manuals repo, the
security-doc repo does not have a README.rst file.

Hence, this patch set adds README.rst to security-doc with all the information
needed for a new contributor.

The README.rst in this patch set will also create a nice landing page for the
security-doc repo in GitHub at https://github.com/openstack/security-doc.

Change-Id: I6a0222be0e1f1378f36b2a31011391ae4bbec164
Closes-Bug: 1545355

README.rst

@@ -0,0 +1,77 @@
+OpenStack Security Documentation
+++++++++++++++++++++++++++++++++
+
+This repository contains the OpenStack Security documentation.
+
+For more details, see the `OpenStack Documentation Contributor
+Guide <http://docs.openstack.org/contributor-guide/>`_.
+
+It includes these manuals:
+
+ * Security Guide
+ * Security Notes
+
+The Security Notes are published by the OpenStack Security Project (OSSP) to
+advise users of security related issues. For more information refer
+https://wiki.openstack.org/wiki/Security_Notes and
+https://wiki.openstack.org/wiki/Security/Security_Note_Process.
+
+Security Advisories are issued by the Vulnerability Management Team (VMT). For
+more information about OpenStack's Vulnerability Management Team (VMT) refer
+https://security.openstack.org/vmt-process.html.
+
+Directory Structure
+-------------------
+Security Guide is in the directory ``security-guide``, which source files in
+RST format in the directory ``security-guide/source``.
+
+The security notes are in the directory ``security-notes``.
+
+
+Testing of changes and building of the guides
+=============================================
+
+Install the python tox package and run ``tox`` from the top-level
+directory to use the same tests that are done as part of our Jenkins
+gating jobs.
+
+    tox
+
+
+Contributing
+============
+
+Our community welcomes all people interested in open source cloud
+computing, and encourages you to join the `OpenStack Foundation
+<http://www.openstack.org/join>`_.
+
+The best way to get involved with the community is to talk with others
+online or at a meet up and offer contributions through our processes,
+the `OpenStack wiki <http://wiki.openstack.org>`_, blogs, or on IRC at
+``#openstack`` on ``irc.freenode.net``.
+
+We welcome all types of contributions, from blueprint designs to
+documentation to testing to deployment scripts.
+
+If you would like to contribute to the documents, please see the
+`OpenStack Documentation contributor guide
+<http://docs.openstack.org/contributor-guide/>`_.
+
+
+Bugs
+====
+
+Bugs should be filed on Launchpad, not GitHub:
+
+   https://bugs.launchpad.net/openstack-manuals
+
+If you find a security issue in OpenStack, not in the contents of the Security
+Guide, please see  `How to Report Security Issues to OpenStack
+<https://security.openstack.org/>`_.
+
+
+Installing
+==========
+
+Refer to http://docs.openstack.org/security-guide to see where these documents
+are published and to learn more about the OpenStack Security Guide.