Update README.md and documentation

Signed-off-by: Arnaud Porterie <arnaud.porterie@docker.com>

README.md

@@ -1,4 +1,55 @@
-distribution
+Distribution
 ============
 
-The Docker toolset to pack, ship, store, and deliver content
+The Docker toolset to pack, ship, store, and deliver content.
+
+Planned content for this repository:
+
+* Distribution related specifications
+    - Image format
+    - JSON registry API
+* Registry implementation: a Golang implementation of the JSON API
+* Client libraries to consume conforming implementations of the JSON API
+
+# Ongoing open sprint
+
+### What is an open sprint?
+
+The open sprint is a focused effort of a small group of people to kick-off a new project, while commiting to becoming maintainers of the resulting work.
+
+**Having a dedicated team work on the subject doesn't mean that you, the community, cannot contribute!** We need your input to make the best use of the sprint, and focus our work on what matters for you. For this particular topic:
+
+* Come discuss on IRC: #docker-distribution on FreeNode
+* Submit your ideas, and upvote those you think matter the most on [Google Moderator](https://www.google.com/moderator/?authuser=1#16/e=2165c3)
+
+### Goal of the distribution sprint
+
+Design a professional grade and extensible content distribution system, that allow users to:
+
+* Enjoy an efficient, secured and reliable way to store, manage, package and exchange content
+* Hack/roll their own on top of healthy open-source components
+* Implement their own home made solution through good specs, and solid extensions mechanism.
+
+### Schedule and expected output
+
+The Open Sprint will start on **Monday December 29th**, and end on **Friday January 16th**.
+
+What we want to achieve as a result is:
+
+* Tactical fixes of today's frustrations in the existing Docker codebase
+  - This includes a throrough review of [docker/docker#9784](https://github.com/docker/docker/pull/9784) by core maintainers
+
+* Laying the base of a new distribution subsystem, living independently, and with a well defined group of maintainers. This is the purpose of this repository, which aims at hosting:
+  - A specification of the v2 image format
+  - A specification of the JSON/HTTP protocol
+  - Server-side Go implementation of the v2 registry
+  - Client-side Go packages to consume this new API
+  - Standalone binaries providing content distribution functionalities outside of Docker
+
+### How will this integrate with Docker engine?
+
+Building awesome, independent, and well maintained distribution tools should give Docker core maintainers enough incentive to switch to the newly develop subsystem. We make no assumptions on a given date or milestone as urgency should be fixed through [docker/docker#9784](https://github.com/docker/docker/pull/9784), and in order to maintain focus on producing a top quality alternative.
+
+### Relevant documents
+
+* [Analysis of current state and goals](docs/opensprint/kickoff.md)