Break out contributing docs

Author: nyonson

CONTRIBUTING.md

@@ -0,0 +1,25 @@
+# Contributing
+
+We generally follow the contribution guidelines of [rust-bitcoin](https://github.com/rust-bitcoin/rust-bitcoin/blob/master/CONTRIBUTING.md).
+
+## Development Workflow
+
+We use [`just`](https://just.systems/man/en/) for running development workflow commands. Run `just` from your shell to see the list of available commands.
+
+### Git Hooks
+
+To catch errors before running CI, we provide git hooks. To use them:
+
+```bash
+git config --local core.hooksPath githooks/
+```
+
+Alternatively, add symlinks in your `.git/hooks` directory to any of the githooks we provide.
+
+## Integration Tests with Bitcoin Core
+
+The `bitcoind-tests/` package contains integration tests that run against real Bitcoin Core instances. A separate package is used so that bitcoind version flags don't pollute the rust-psbt crate. The package is not a member of the workspace so that it doesn't effect dependency version resolution.
+
+### NixOS Users
+
+The auto-downloaded Bitcoin Core binaries don't work on NixOS due to dynamic linking requirements. If you're on NixOS you could manually configure the `BITCOIND_EXE` environment variable to use a Nix-provided `bitcoind` of the correct version.

README.md

@@ -3,46 +3,16 @@
 Implementation of the Partially Signed Bitcoin Transaction Format as defined in [BIP-174] and
 PSBT version 2 as defined in [BIP-370].
 
-## Contributing
-
-For now we more or less just follow the contribution guidelines of 
-[rust-bitcoin](https://github.com/rust-bitcoin/rust-bitcoin/CONTRIBUTING.md).
-
-### Minimum Supported Rust Version (MSRV)
+## Minimum Supported Rust Version (MSRV)
 
 This library should always compile with any combination of features on **Rust 1.74.0**.
 
 To build with the MSRV you will likely need to pin a bunch of dependencies, see `./contrib/test.sh`
 for the current list.
 
-### Just
-
-We support [`just`](https://just.systems/man/en/) for running dev workflow commands. Run `just` from
-your shell to see list available sub-commands.
-
-### Building the docs
-
-We build docs with the nightly toolchain, you may wish to use the following shell alias to check
-your documentation changes build correctly.
-
-```
-alias build-docs='RUSTDOCFLAGS="--cfg docsrs" cargo +nightly rustdoc --features="$FEATURES" -- -D rustdoc::broken-intra-doc-links'
-```
-
-### Githooks
-
-To assist devs in catching errors _before_ running CI we provide some githooks. If you do not
-already have locally configured githooks you can use the ones in this repository by running, in the
-root directory of the repository:
-```
-git config --local core.hooksPath githooks/
-```
-
-Alternatively add symlinks in your `.git/hooks` directory to any of the githooks we provide.
-
-### rustfmt
+## Contributing
 
-We format with `cargo +nightly fmt`, see `./rusntfmt.toml` for the current configuration.
+Contributions are welcome! Please see [CONTRIBUTING.md](CONTRIBUTING.md) for guidelines.
 
 ## License