message: Update README to add repository guide
diff: This is the main repo for [Cardstack](https://www.cardstack.com/), an open source application architecture for building cohesive experiences, including payments, on open, decentralized infrastructure.
  -Join the discussion around developing on the Cardstack framework on [Discord](https://discord.gg/apepFje), and read our documentation on [docs.cardstack.com](https://docs.cardstack.com).
  +Join the discussion around developing on the Cardstack framework on [Discord](https://discord.gg/apepFje), and read our documentation on [docs.cardstack.com](https://docs.cardstack.com). (Note: documentation refers to [Cardstack v2](https://github.com/cardstack/cardstack/tree/cardstack-v2-eol). The main branch of this respository has in-progress work on v3 of Cardstack.)
  ## Orientation
  @@ -27,6 +27,49 @@ In development, we use `lerna` to manage the inter-dependencies of all the packa
  4. Launch the typescript compiler with `yarn compile --watch`
  5. Start ember-cli and the hub node server with `yarn start` and/or run tests with `yarn test`
  +## Understanding the respositories under the Cardstack organization
  +
  +The following summary offers an overview of where development is currently ongoing at Cardstack:
  +
  +https://github.com/cardstack/card-protocol-xdai
  +- The Layer 2 contracts for the card protocol live here including
  + - PrepaidCardManager contract
  + - RevenuePool contract
  + - L2 Token contract
  + - SPEND token contract
  + - BridgeUtilities contract (facilitates token bridge contract)
  +
  +https://github.com/cardstack/tokenbridge-contracts
  + - The home bridge and foreign bridge token contracts
  +
  +https://github.com/cardstack/card-protocol-relay-service
  + - our gnosis relay service, forked to provide additional prepaid card manager
  + API's that support gasless interactions with our PrepaidCardManager contract
  +
  +https://github.com/cardstack/safe-transaction-service
  + - our gnosis transaction service, this was forked to provide transaction
  + service for Sokol (xDai uses the gnosis hosted transaction service)
  +
  +https://github.com/cardstack/cardstack
  + - our monorepo that contains our CardPay Dapp (as well as eventually
  + cardstack hub runtime). Work on the "card compiler" is also occurring in PRs
  + of this repository. A proof-of-concept for the dapp was developed
  + here: https://github.com/cardstack/card-pay/tree/update-UI-depot
  +
  +https://github.com/cardstack/cardwallet
  + - our rainbow wallet fork that supplies our mobile client experience.
  + Currently it is focused around interacting with Layer 1 contracts,
  + eventually we see it as interacting with the Layer2 protocol as well.
  + A proof-of-concept was developed here: https://github.com/cardstack/rainbow/branches
  +
  +https://github.com/cardstack/infra
  + - Holds our terraform scripts to provision AWS and cloudflare (and
  + eventually GCP) services for our infrastructure.
  +
  +https://github.com/cardstack/boxel
  + - our web UI component library
  +
  +
  ## Project-wide Policy and Community Governance
  Cardstack follows semantic versioning. As a young, pre-1.0 project, this means you can continue to expect breaking changes in minor releases. Each package should endeavor to include a CHANGELOG.md once it begins to have a non-trivial number of external users.
  