Add a CONTRIBUTING file

CONTRIBUTING.rst

@@ -0,0 +1,44 @@
+Contributing to biboumi
+=======================
+
+Biboumi’s main workplace is at https://lab.louiz.org/louiz/biboumi
+
+The repository is also mirrored on other websites, for example on github, but
+that’s mainly for the convenience of users.
+
+Before doing anything, you can come on the `XMPP chatroom`_ to discuss your
+changes, issues or ideas.
+
+Bug reports, feature requests
+-----------------------------
+To open a bug report, or a feature request, please do so on
+`our gitlab’s bug tracker`_.
+
+If the issue you’re reporting may have security implications, please select
+the “confidential” flag in your bug report.
+
+
+Code
+----
+To contribute code, you can do so using git: commit your changes on any
+publicly available git repository and communicate us its address.  This
+can be done with a `gitlab merge request`_, or a `github pull request`_
+or just by sending a message into the `XMPP chatroom`_.
+
+
+Coding style
+------------
+Please try to follow the existing style:
+
+- Use only spaces, not tabs.
+- Curly brackets are on their own lines.
+- Use this-> everywhere it’s possible.
+- Don’t start class attributes with “m_” or similar.
+- Type names are in PascalCase.
+- Everything else is in snake_case.
+
+
+.. _our gitlab’s bug tracker: https://lab.louiz.org/louiz/biboumi/issues/new
+.. _gitlab merge request: https://lab.louiz.org/louiz/biboumi/merge_requests/new
+.. _github pull request: https://github.com/louiz/biboumi/pulls
+.. _XMPP chatroom: xmpp:biboumi@muc.poez.io

README.rst

@@ -52,13 +52,7 @@ Contact/Support
 * XMPP ChatRoom: biboumi@muc.poez.io
 * Report a bug:  https://lab.louiz.org/louiz/biboumi/issues/new
 
-To contribute, the preferred way is to commit your changes on some
-publicly-available git repository (a fork on gitlab or github or on your own
-repository) and to notify the developers with a ticket on the bug tracker,
-or a merge request on gitlab or a pull request on github.
-
-Optionally you can come discuss your changes on the XMPP chat room,
-beforehand.
+Also, see the `contributing`_ page.
 
 
 Licence
@@ -71,3 +65,4 @@ Please read the COPYING file for details.
 
 .. _INSTALL: INSTALL.rst
 .. _the documentation: doc/biboumi.1.rst
+.. _contributing: CONTRIBUTING.rst