Added doc on how to contribute to the documentation (#920)

* added doc on how to contribute to the documentation

docs/development/updating-documentation.md

@@ -0,0 +1,55 @@
+# Updating Documentation
+
+All documentation for `etcd-druid` resides in [docs](https://github.com/gardener/etcd-druid/tree/master/docs) directory. If you wish to update the existing documentation or create new documentation files then read on.
+
+## Prerequisite: Setup Mkdocs locally
+[Material for Mkdocs](https://squidfunk.github.io/mkdocs-material/) is used to generate GitHub Pages from all the Markdown files present under the [docs](https://github.com/gardener/etcd-druid/tree/master/docs) directory. To locally validate that the documentation renders correctly, it is recommended that you perform the following setup.
+
+* Install python3 if not already installed.
+* Setup a virtual environment via 
+
+```bash
+python -m venv venv
+```
+
+* Activate the virtual environment 
+
+```bash
+source venv/bin/activate
+```
+
+* In the virtual environment install the packages.
+
+```bash
+(venv) > pip install mkdocs-material
+(venv) > pip install pymdown-extensions
+(venv) > pip install mkdocs-glightbox
+(venv) > pip install mkdocs-pymdownx-material-extras
+```
+
+!!! note
+    Complete list of packages installed should be in sync with [Github Actions Configuration](https://github.com/gardener/etcd-druid/blob/master/.github/workflows/publish-docs.yml#L23-L27).
+* Serve the documentation
+
+```bash
+(venv) > mkdocs serve
+```
+You can now view the rendered documentation at `localhost:8000`. Any changes that you make to the docs will get hot-reloaded and you can immediately view the changes.
+
+## Updating Documentation
+
+All documentation _should_ be in `markdown` _only_. Ensure that you take care of the following:
+
+* The [index.md](https://github.com/gardener/etcd-druid/blob/master/docs/index.md) is the home page for the documentation rendered as Github Pages. Please do not remove this file.
+* If you are using a new feature (that is not already used) by `Mkdocs` then ensure that it is properly configured in [mkdocs.yml](https://github.com/gardener/etcd-druid/blob/master/mkdocs.yml). Additionally, if new plugins or Markdown extensions are used, make sure that you update the [Github Actions Configuration](https://github.com/gardener/etcd-druid/blob/master/.github/workflows/publish-docs.yml#L23-L27) accordingly.
+* If new files are being added and you wish to show these files in Github Pages then ensure that you have added them under appropriate sections in the [navigation](https://github.com/gardener/etcd-druid/blob/master/mkdocs.yml#L70) section of `mkdocs.yml`.
+* If you are linking to any file outside the [docs](https://github.com/gardener/etcd-druid/tree/master/docs) directory then relative links will not work on Github Pages. Please get the `https` link to the file or section of the file that you wish to link.
+
+## Raise a Pull Request
+
+Once you have made the documentation changes then follow the guide on [how to raise a PR](raising-a-pr.md).
+
+!!! info
+    Once the documentation update PR has been merged, you will be able to see the updated documentation [here](https://gardener.github.io/etcd-druid/).
+
+

mkdocs.yml

@@ -92,6 +92,7 @@ nav:
       - Raising a PR: development/raising-a-pr.md
       - Manage Dependencies: development/dependency-management.md
       - Testing: development/testing.md
+      - Updating documentation: development/updating-documentation.md
   - API Reference:
       - Etcd Druid API: api-reference/etcd-druid-api.md
   - Monitoring: