Add a README

README.md

+microchat
+===
+
+An experimental minimalistic ephemeral web-based chat. 
+
+It is meant as a very quick way to exchange real-time messages with
+somewhat-trusted parties, with a few peculiar characteristics:
+
+* no custom application required, it works on desktop and mobile with
+  just a web browser;
+* no user registration process, no connections to external identities
+  (emails) or any other form of long-term user identity;
+* based on a *rendez-vous* workflow, participants agree on a "secret"
+  beforehand, which in this case is the room name;
+* no logs, messages are not persisted in any form except in the
+  browser window of the participants: when it is closed, they're gone
+  -- no room history is kept for new participants.
+
+There is no access control on rooms: if you know a room name, you can
+join it. This is partially mitigated by making room membership
+prominently visible.
+
+The chat implements end-to-end encryption, primarily as a way to make
+it safe against corporate proxies and such, and to avoid liabilities
+for instance operators: participants still need to trust the instance
+operator, as it may be serving a back-doored version of the
+application.
+
+From a forensic perspective, all it requires from the participant is
+the usage of a browser "incognito" window, to avoid leaving the
+instance name in the browser history.