Added CONTRIBUTING.md (#44)

* Added CONTRIBUTING.md

* Added link to CONTRIBUTING.md

Co-authored-by: Jason Ozias <[email protected]>

Author: CraZySacX

CONTRIBUTING.md

@@ -0,0 +1,28 @@
+# Contributing to vergen
+1. Ensure you have `cargo-clippy` and `rustfmt` installed.  These can be installed via rustup if you don't already have them.
+1. Fork the repository
+1. Run the following to clone and setup the repository.  There are submodules in the testdata directory used for testing specific git scenarios
+
+    ```
+    git clone [email protected]:<your fork>/vergen.git
+    cd vergen.git
+    git submodule update --init
+    ```
+
+1. Install `cargo-all-features`
+
+    ```
+    cargo install cargo-all-features
+    ```
+
+1. Make your changes
+1. Before submitting a PR, make sure you have at least run the following
+
+    ```
+    cargo fmt
+    cargo clippy --all
+    cargo build-all-features
+    cargo test-all-features
+    ```
+
+1. Push your changes to your fork and submit a PR.

README.md

@@ -52,6 +52,9 @@ cargo:rerun-if-changed=/Users/yoda/projects/rust-lang/vergen/.git/refs/heads/fea
 ## Example Usage
 See the documentation at [docs.rs](https://docs.rs/vergen/3.2.0/vergen/#cargo-key-build-script-output) for example usage
 
+## Contributing
+See the documentation at [CONTRIBUTING.md](CONTRIBUTING.md)
+
 ## License
 
 Licensed under either of