Merge pull request #15 from njam/docs-release

Add docs about releasing a new version

Author: njam

HACKING.md

@@ -0,0 +1,7 @@
+Release a New Version
+---------------------
+1. Update `CHANGELOG.md` and `Cargo.toml`.
+2. Create a tag `vX.X.X` and push it to Github.
+3. Check out the tag locally, then run `cargo publish` to publish to [crates.io].
+
+[crates.io]: https://crates.io/crates/slog-json