Add onboarding.rst and improve gitlab.rst

Add documentation file which describes onboarding process in the Oniro Project

Signed-off-by: Grzegorz Gwóźdź <grzegorz.gwozdz@huawei.com>

contributing/gitlab.rst

@@ -21,6 +21,24 @@ with proposed changes and raise a merge request against the forked repository.
 More generic information you can find on the Gitlab's documentation as part of
 `"Merge requests workflow" <https://docs.gitlab.com/ee/development/contributing/merge_request_workflow.html>`_.
 
+Git setup
+*********
+
+Clone your fork locally, enter the directory with it and set:
+
+.. code-block:: bash
+
+    $ git config --local user.email <your_eclipse_account_email>
+    $ git config --local user.name <your_eclipse_full_name>  
+
+
+To push and pull over HTTPS with Git using your account, you must set a password
+or `a Personal Access Token <https://docs.gitlab.com/ee/user/profile/personal_access_tokens.html>`_
+to use instead.
+
+If you want to push or pull repositories using SSH, you have to
+`add a SSH key <https://docs.gitlab.com/ee/user/ssh.html>`_ to your profile.
+
 Commit Guidelines
 *****************
 
@@ -145,3 +163,21 @@ is to maintain the RestructuredText file format. Text files that are not meant t
 as part of the project's documentation can be written in `Markdown <https://daringfireball.net/projects/markdown/>`_.
 For example, a repository ``README`` file can be written in Markdown as it
 doesn't end up compiled in the project-wide documentation.
+
+Creating the Merge Request
+--------------------------
+
+If you push the branch with your changes to your fork, you are ready to prepare a merge request.
+
+1. Go to your repository in an internet browser. 
+
+#. Create a Merge Request by clicking ``Merge Requests`` on left toolbar
+   and press ``New merge request``. Add an explainable description and create a merge request.
+   Alternatively, you can enter the website of your fork. You should see a message that you 
+   pushed your branch to the repository. In the same section you can press ``Create merge request``.
+#. Before merging, it has to be reviewed and approved by 2 of |main_project_name| repository
+   maintainers. Read their review and add any required changes to your merge request. 
+#. After you polish your merge request, the maintainers will run the pipelines which check
+   if your changes do not break the project and approve them. If everything is correct, your work
+   is merged to the main project. Remember that changes which were added on top of
+   changes introduced in the MR, should be squashed into the initial commit.

contributing/index.rst

@@ -16,6 +16,7 @@ requirements.
 .. toctree::
    :maxdepth: 1
    
+   onboarding
    gitlab
    reuse
    dco

contributing/onboarding.rst

+.. SPDX-FileCopyrightText: Huawei Inc.
+..
+.. SPDX-License-Identifier: CC-BY-4.0
+
+.. include:: ../definitions.rst
+
+Onboarding procedures
+#####################
+This page describes onboarding procedures for new contributors who would like to
+join the |main_project_name| 
+
+
+.. contents::
+   :depth: 2
+
+Setting up
+**********
+
+Creating an account on Eclipse 
+------------------------------
+
+Head to the 
+`Eclipse foundation website <https://accounts.eclipse.org/user/register?destination=user/login>`_ 
+and set up an account by entering your:
+
+- Email
+- Username
+- Full name
+- Organization
+- Password
+- Country
+
+Then read and check the box to agree to Terms of Use, Privacy Policy and Code of Conduct. 
+When you complete that, follow the instructions sent to your email to activate the account.
+
+Signing the ECA
+---------------
+
+In order to contribute to the |main_project_name| you need to sign the 
+`Eclipse Contributor Agreement  <https://accounts.eclipse.org/user/eca>`_, 
+which describes the terms under which you can contribute to the project.
+
+If you sign this ECA, you confirm your legal rights to submit the code to the project.
+You also provide license to your contributions to Eclipse and specified users, however
+you still own your contributions.
+
+EF Gitlab Account Setup
+-----------------------
+
+Now you can go to `the Oniro Gitlab <https://gitlab.eclipse.org/eclipse/oniro-core/oniro>`_ .
+You should use the account that was created in the previous step to log in.
+
+For further information, go to the :doc:`Gitlab section <gitlab>`.