[gnome-contacts] README: add more info for (new) contributors.

[Niels De Graef <nielsdg src gnome org>]

commit 73cbfcb0fe97b0c4401c74c041876d50eb0ab807
Author: Niels De Graef <nielsdegraef gmail com>
Date:   Sun May 27 15:47:43 2018 +0200

    README: add more info for (new) contributors.
    
    Fixes issue #97.

 README.md | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)
---
diff --git a/README.md b/README.md
index c71d9ff..c8b6cce 100644
--- a/README.md
+++ b/README.md
@@ -10,19 +10,30 @@ ninja -C build
 ninja -C build install
 ```
 
-## Issue tracker
+## Contributing
 The code and issue tracker of Contacts can be found at the
 [gnome-contacts repository](https://gitlab.gnome.org/GNOME/gnome-contacts) on
-the GNOME GitLab instance.
+GNOME's GitLab instance.
 
-If you find a bug in Contacts, please file an issue with reproducible steps and
-the version of Contacts (shown in the About dialog, or by running
-`gnome-contacts --version`).
+### Reporting issues
+If you find a bug in Contacts, please [file an
+issue](https://gitlab.gnome.org/GNOME/gnome-contacts/issues) with reproducible
+steps and the version of Contacts you were using at that point.
 
+### Developers
 If you want to contribute functionality or bug fixes to Contacts, you should
-fork the Contacts repository, work on a separate branch, and then open a
-merge request (MR) on our GitLab repository. If the MR fixes an existing issue,
-please refer to that issue in the description.
+fork the Contacts repository, commit your changes, and then [open a merge
+request](https://gitlab.gnome.org/GNOME/gnome-contacts/merge_requests/new) (MR).
+If the MR fixes an existing issue, please refer to that issue in the
+description of the commit.
+
+### Translators
+If GNOME Contacts is not translated in your language or you believe that the
+current translation has errors, then you can join one of the various
+translation teams in GNOME. Translators do not commit directly to Git, but are
+advised to use our separate translation infrastructure instead. [More info can
+be found at GNOME's Wiki page on the translation
+project](https://wiki.gnome.org/TranslationProject/JoiningTranslation).
 
 ## More information
 Contacts has its own web page on https://wiki.gnome.org/Apps/Contacts.
@@ -30,3 +41,7 @@ Contacts has its own web page on https://wiki.gnome.org/Apps/Contacts.
 To discuss issues with developers and other users, you can subscribe to the
 [mailing list](https://mail.gnome.org/mailman/listinfo/gnome-contacts-list)
 or join [#contacts](irc://irc.gnome.org/contacts) on irc.gnome.org.
+
+If you would like to get involved with GNOME projects, please also visit our
+[Newcomers page](https://wiki.gnome.org/TranslationProject/JoiningTranslation)
+on the Wiki.