added how to contribute page

docs/contribute.md

+# Contribute To Documentation
+
+There are several ways to contribute to the documentation
+based on the user's proficiency with Git/GitLab. From the least to most proficient, these are:
+
+## Forking Repository
+
+Since this documentation is built with [MkDocs Material][1], you need to install it first. See the [official installation instructions][2].
+
+Once you have MkDocs Material installed,
+proceed with the following steps:
+
+### Fork Repository
+See GitLab @ ICS MU for details. This will create your own clone of our repository where you will be able to make changes. Once you are happy with your changes, use GitLab to submit them to our original repository.
+
+### Clone Repository
+
+```console
+# after creating your own copy of the repository on GitLab
+git clone git@gitlab.ics.muni.cz:einfra-docs/documentation.git
+```
+
+### Create New Branch
+
+```console
+# in `mkdocs-material`
+git checkout -b my_change
+```
+
+### Make Changes & Run Local Server
+
+```console
+# in `mkdocs-material`
+docker run --rm -it -p 8000:8000 -v ${PWD}:/docs squidfunk/mkdocs-material
+```
+
+!!! note
+    Edits will be shown live in your browser window, no need to restart the server.
+
+### Commit and Push Changes
+
+```console
+git commit -am "Commit message"
+git push origin my_change
+```
+
+### Submit Changes
+
+Create a *Merge Request* via GitLab @ ICS MU.
+
+## Simple Merge Request
+
+This option is suitable for less extensive contribution
+(e.g. a section or a subsection) of an already existing page).
+
+In this case, simply:
+
+1. click the **Edit this page**
+under the Table of Content on the right side of the respective page;
+1. make the changes;
+1. create a merge request.
+
+## Contacting Support
+
+The easiest way is to contact us at [support@e-infra.cz][3] with your contribution.
+
+[1]: https://github.com/squidfunk/mkdocs-material
+[2]: https://squidfunk.github.io/mkdocs-material/getting-started/
+[3]: mailto:support@e-infra.cz

mkdocs.yml

@@ -56,7 +56,9 @@ nav:
     - Sensitive: '!include ./docs/compute/sensitive/mkdocs.yml'
   - Storage: '!include ./docs/storage/mkdocs.yml'
   - Managed services: '!include ./docs/managed/mkdocs.yml'
-  - About Us: about-us.md
+  - General Information:
+    - About Us: about-us.md
+    - How To Contribute: contribute.md
 
 #extra:
 #  disqus: 'test-3whnesz3gq'

[Jan Siwiec]

related to #1