Merge ~gabrielcocenza/juju-lint:contributing into juju-lint:master

[Gabriel Cocenza]

adding CONTRIBUTING.md to the project.

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

[Alvaro Uria (aluria)]

+1

review: Approve

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Change successfully merged at revision 112591bbc7cf5303743eadaccbec5442f2541cac

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
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+# Contributing
+
+## Overview
+
+This documents explains the processes and practices recommended for contributing enhancements to
+this project.
+
+- Generally, before developing enhancements to this project, you should consider [report a bug
+  ](https://bugs.launchpad.net/juju-lint) explaining your use case.
+- All enhancements require review before being merged. Code review typically examines
+  - code quality
+  - test coverage
+  - documentation
+- Please help us out in ensuring easy to review branches by rebasing your pull request branch onto
+  the `master` branch. This also avoids merge commits and creates a linear Git commit history.
+
+### Developing
+
+Clone this repository:
+```shell
+git clone git+ssh://<LAUNCHPAD_USER>@git.launchpad.net/juju-lint
+cd juju-lint/
+```
+
+You can use the environments created by `tox` for development:
+
+```shell
+tox --notest -e unit
+source .tox/unit/bin/activate
+```
+
+After making your changes you can run the CI without the need of building and installing the snap by using:
+
+```shell
+python3 -m jujulint.cli <PATH_TO_YAML> -c <PATH_TO_RULE_FILE> -l debug
+```
+
+
+### Testing
+
+```shell
+make lint            # check code style
+make test            # unit tests
+make build           # build the snap
+make clean           # clean the snapcraft lxd containers
+```
+
+## Canonical Contributor Agreement
+
+Canonical welcomes contributions to the juju-lint. Please check out our [contributor agreement](https://ubuntu.com/legal/contributors) if you're interested in contributing to the solution.