Added CONTRIBUTING.md (#19)

Signed-off-by: Francesco Guardiani <francescoguard@gmail.com>

CONTRIBUTING.md

@@ -0,0 +1,129 @@
+# Contributing to CloudEvents SDK Rust
+
+This page contains information about reporting issues, how to suggest changes as
+well as the guidelines we follow for how our documents are formatted.
+
+## Table of Contents
+
+- [Reporting an Issue](#reporting-an-issue)
+- [Preparing the environment](#preparing-the-environment)
+- [Suggesting a Change](#suggesting-a-change)
+
+## Reporting an Issue
+
+To report an issue, or to suggest an idea for a change that you haven't had time
+to write-up yet, open an [issue](https://github.com/cloudevents/sdk-rust/issues). It
+is best to check our existing
+[issues](https://github.com/cloudevents/sdk-rust/issues) first to see if a similar
+one has already been opened and discussed.
+
+## Preparing the environment
+
+In order to start developing this project, 
+you need to install the Rust tooling using [rustup](https://rustup.rs/).
+
+### Development commands
+
+To build the project:
+
+```sh
+cargo build --all-features
+```
+
+To run all tests:
+
+```sh
+cargo test --all-features
+```
+
+To build and open the documentation:
+
+```sh
+cargo doc --lib --open
+```
+
+To run the code formatter:
+
+```sh
+cargo fmt
+```
+
+## Suggesting a change
+
+To suggest a change to this repository, submit a
+[pull request](https://github.com/cloudevents/spec/pulls)(PR) with the complete
+set of changes you'd like to see. See the
+[Spec Formatting Conventions](#spec-formatting-conventions) section for the
+guidelines we follow for how documents are formatted.
+
+Each PR must be signed per the following section.
+
+### Sign your work
+
+The sign-off is a simple line at the end of the explanation for the patch. Your
+signature certifies that you wrote the patch or otherwise have the right to pass
+it on as an open-source patch. The rules are pretty simple: if you can certify
+the below (from [developercertificate.org](http://developercertificate.org/)):
+
+```
+Developer Certificate of Origin
+Version 1.1
+
+Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
+1 Letterman Drive
+Suite D4700
+San Francisco, CA, 94129
+
+Everyone is permitted to copy and distribute verbatim copies of this
+license document, but changing it is not allowed.
+
+Developer's Certificate of Origin 1.1
+
+By making a contribution to this project, I certify that:
+
+(a) The contribution was created in whole or in part by me and I
+    have the right to submit it under the open source license
+    indicated in the file; or
+
+(b) The contribution is based upon previous work that, to the best
+    of my knowledge, is covered under an appropriate open source
+    license and I have the right under that license to submit that
+    work with modifications, whether created in whole or in part
+    by me, under the same open source license (unless I am
+    permitted to submit under a different license), as indicated
+    in the file; or
+
+(c) The contribution was provided directly to me by some other
+    person who certified (a), (b) or (c) and I have not modified
+    it.
+
+(d) I understand and agree that this project and the contribution
+    are public and that a record of the contribution (including all
+    personal information I submit with it, including my sign-off) is
+    maintained indefinitely and may be redistributed consistent with
+    this project or the open source license(s) involved.
+```
+
+Then you just add a line to every git commit message:
+
+    Signed-off-by: Joe Smith <joe.smith@email.com>
+
+Use your real name (sorry, no pseudonyms or anonymous contributions.)
+
+If you set your `user.name` and `user.email` git configs, you can sign your
+commit automatically with `git commit -s`.
+
+Note: If your git config information is set properly then viewing the `git log`
+information for your commit will look something like this:
+
+```
+Author: Joe Smith <joe.smith@email.com>
+Date:   Thu Feb 2 11:41:15 2018 -0800
+
+    Update README
+
+    Signed-off-by: Joe Smith <joe.smith@email.com>
+```
+
+Notice the `Author` and `Signed-off-by` lines match. If they don't your PR will
+be rejected by the automated DCO check.

README.md

@@ -1,3 +1,7 @@
-# CloudEvents Rust SDK
+# CloudEvents SDK Rust
 
 Work in progress SDK for [CloudEvents](https://github.com/cloudevents/spec)
+
+## Development & Contributing
+
+If you're interested in contributing to sdk-rust, look at [Contributing documentation](CONTRIBUTING.md)