Added contribution guide and overview to docs

README.md

@@ -1,6 +1,24 @@
 kepi
 ====
 
-kepi is an ActivityPub daemon, written in Python.
+kepi is an ActivityPub daemon.
+
+[ActivityPub](https://www.w3.org/TR/activitypub/) is a standard protocol
+for integrating social media across Internet sites.
+
+For example, you might post an article. Someone else on another site
+might reply to it, and someone else might "like" it. Someone else again
+might "follow" you, in order to get notifications when you post
+anything else.
+
+kepi runs in the background on your server, distributing your messages
+to other sites, and receiving their responses.
 
 * [Installation guide](docs/installation.md)
+* [Source](https://gitlab.com/marnanel/kepi/)
+
+If you'd like to contribute, there's lots to do. Find something on the
+[bug tracker](https://gitlab.com/marnanel/kepi/issues?label_name%5B%5D=newbie)
+and dive in. If you'd like a gentler learning curve, look
+for
+[bugs marked "newbie"](https://gitlab.com/marnanel/kepi/issues?label_name%5B%5D=newbie)

docs/installation.md

@@ -123,3 +123,6 @@ Going on from here
 gunicorn itself isn't suitable for facing the public internet.
 You'll need to put something like nginx in front of it.
 This document should explain that, and it will at some point.
+
+[Back](../README.md)
+