cloud-hypervisor: Add a contributing guide

Signed-off-by: Samuel Ortiz <[email protected]>

CONTRIBUTING.md

@@ -0,0 +1,92 @@
+# Contributing to Cloud Hypervisor
+
+Cloud Hypervisor is an open source project licensed under the [Apache v2 License](https://opensource.org/licenses/Apache-2.0) and the [BSD 3 Clause](https://opensource.org/licenses/BSD-3-Clause) license.
+
+## Coding Style
+
+We follow the [Rust Style](https://github.com/rust-dev-tools/fmt-rfcs/blob/master/guide/guide.md)
+convention and enforce it through the Continuous Integration (CI) process calling into `rustfmt`
+for each submitted Pull Request (PR).
+
+## Certificate of Origin
+
+In order to get a clear contribution chain of trust we use the [signed-off-by language] (https://01.org/community/signed-process)
+used by the Linux kernel project.
+
+## Patch format
+
+Beside the signed-off-by footer, we expect each patch to comply with the following format:
+
+```
+<component>: Change summary
+
+More detailed explanation of your changes: Why and how.
+Wrap it to 72 characters.
+See http://chris.beams.io/posts/git-commit/
+for some more good pieces of advice.
+
+Signed-off-by: <[email protected]>
+```
+
+For example:
+
+```
+vm-virtio: Reset underlying device on driver request
+    
+If the driver triggers a reset by writing zero into the status register
+then reset the underlying device if supported. A device reset also
+requires resetting various aspects of the queue.
+    
+In order to be able to do a subsequent reactivate it is required to
+reclaim certain resources (interrupt and queue EventFDs.) If a device
+reset is requested by the driver but the underlying device does not
+support it then generate an error as the driver would not be able to
+configure it anyway.
+    
+Signed-off-by: Rob Bradford <[email protected]>
+```
+
+## Pull requests
+
+Cloud Hypervisor uses the “fork-and-pull” development model. Follow these steps if
+you want to merge your changes to `cloud-hypervisor`:
+
+1. Fork the [cloud-hypervisor](https://github.com/intel/cloud-hypervisor) project
+   into your github organization.
+2. Within your fork, create a branch for your contribution.
+3. [Create a pull request](https://help.github.com/articles/creating-a-pull-request-from-a-fork/)
+   against the master branch of the Cloud Hypervisor repository.
+4. Add reviewers to your pull request and then work with your reviewers to address
+   any comments and obtain minimum of 2 [maintainers](MAINTAINERS.md) approvals.
+   To update your pull request amend existing commits whenever applicable and
+   then push the new changes to your pull request branch.
+5. Once the pull request is approved, one of the maintainers will merge it.
+
+## Issue tracking
+
+If you have a problem, please let us know. We recommend using
+[github issues](https://github.com/intel/cloud-hypervisor/issues/new) for formally
+reporting and documenting them.
+
+To quickly and informally bring something up to us, you can also reach out on [Slack](https://cloud-hypervisor.slack.com).
+
+## Closing issues
+
+You can either close issues manually by adding the fixing commit SHA1 to the issue
+comments or by adding the `Fixes` keyword to your commit message:
+
+```
+serial: Set terminal in raw mode
+    
+In order to have proper output from the serial, we need to setup the
+terminal in raw mode. When the VM is shutting down, it is also the
+VMM responsibility to set the terminal back into canonical mode if we
+don't want to get any weird behavior from the shell.
+    
+Fixes #88
+	
+Signed-off-by: Sebastien Boeuf <[email protected]>
+```
+
+Then, after the correspoding PR is merged, Github will automatically close that issue when parsing the
+[commit message](https://help.github.com/articles/closing-issues-via-commit-messages/).