spec: merge rust-spec (#252)

spec/light-client/detection/README.md

@@ -0,0 +1,75 @@
+---
+order: 1
+parent:
+  title: Fork Detection
+  order: 2
+---
+
+# Tendermint fork detection and IBC fork detection
+
+## Status
+
+This is a work in progress.
+This directory captures the ongoing work and discussion on fork
+detection both in the context of a Tendermint light node and in the
+context of IBC. It contains the following files
+
+### [detection.md](./detection.md)
+
+a draft of the light node fork detection including "proof of fork"
+  definition, that is, the data structure to submit evidence to full
+  nodes.
+  
+### [discussions.md](./discussions.md)
+
+A collection of ideas and intuitions from recent discussions
+
+- the outcome of recent discussion
+- a sketch of the light client supervisor to provide the context in
+  which fork detection happens
+- a discussion about lightstore semantics
+
+### [req-ibc-detection.md](./req-ibc-detection.md)
+
+- a collection of requirements for fork detection in the IBC
+  context. In particular it contains a section "Required Changes in
+  ICS 007" with necessary updates to ICS 007 to support Tendermint
+  fork detection
+
+### [draft-functions.md](./draft-functions.md)
+
+In order to address the collected requirements, we started to sketch
+some functions that we will need in the future when we specify in more
+detail the
+
+- fork detections
+- proof of fork generation
+- proof of fork verification
+
+on the following components.
+
+- IBC on-chain components
+- Relayer
+
+### TODOs
+
+We decided to merge the files while there are still open points to
+address to record the current state an move forward. In particular,
+the following points need to be addressed:
+
+- <https://github.com/informalsystems/tendermint-rs/pull/479#discussion_r466504876>
+
+- <https://github.com/informalsystems/tendermint-rs/pull/479#discussion_r466493900>
+  
+- <https://github.com/informalsystems/tendermint-rs/pull/479#discussion_r466489045>
+  
+- <https://github.com/informalsystems/tendermint-rs/pull/479#discussion_r466491471>
+  
+Most likely we will write a specification on the light client
+supervisor along the outcomes of
+  
+- <https://github.com/informalsystems/tendermint-rs/pull/509>
+
+that also addresses initialization
+
+- <https://github.com/tendermint/spec/issues/131>