Support sending and displaying typing notifications (#9)

CONTRIBUTING.md

@@ -1 +1,27 @@
 # Contributing to iamb
+
+## Building
+
+You can build `iamb` locally by using `cargo build`.
+
+## Pull Requests
+
+When making changes to `iamb`, please make sure to:
+
+- Add new tests for fixed bugs and new features whenever possible
+- Add new documentation with new features
+
+If you're adding a large amount of new code, please make sure to look at a test
+coverage report and ensure that your tests sufficiently cover your changes.
+
+You can generate an HTML report with [cargo-tarpaulin] by running:
+
+```
+% cargo tarpaulin --avoid-cfg-tarpaulin --out html
+```
+
+## Tests
+
+You can run the unit tests and documentation tests using `cargo test`.
+
+[cargo-tarpaulin]: https://github.com/xd009642/tarpaulin