Add missing README

Author: jonathanpallant

defmt-03/README.md

@@ -0,0 +1,54 @@
+# `defmt`
+
+`defmt` ("de format", short for "deferred formatting") is a highly efficient logging framework that targets resource-constrained devices, like microcontrollers.
+
+For more details about the framework check the book at <https://defmt.ferrous-systems.com>.
+
+This release is a semver-trick compatibility shim that allows packages using `defmt = "0.3"` to inter-operate with packages using `defmt = "1.0"`.
+
+## Setup
+
+### New project
+
+The fastest way to get started with `defmt` is to use our [app-template] to set up a new Cortex-M embedded project.
+
+[app-template]: https://github.com/knurling-rs/app-template
+
+### Existing project
+
+To include `defmt` in your existing project, follow our [Application Setup guide].
+
+[Application Setup guide]: https://defmt.ferrous-systems.com/setup.html
+
+## MSRV
+
+The minimum supported Rust version is 1.76 (or Ferrocene 24.05). `defmt` is tested against the latest stable Rust version and the MSRV.
+
+## Support
+
+`defmt` is part of the [Knurling] project, [Ferrous Systems]' effort at
+improving tooling used to develop for embedded systems.
+
+If you think that our work is useful, consider sponsoring it via [GitHub
+Sponsors].
+
+## License
+
+Licensed under either of
+
+- Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or
+  http://www.apache.org/licenses/LICENSE-2.0)
+
+- MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
+
+at your option.
+
+### Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
+licensed as above, without any additional terms or conditions.
+
+[Knurling]: https://knurling.ferrous-systems.com/
+[Ferrous Systems]: https://ferrous-systems.com/
+[GitHub Sponsors]: https://github.com/sponsors/knurling-rs