Feature/update contribution (#79)

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## Description

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Updated contribution guide

## Type of change

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- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [x] Optimization

## How Has This Been Tested?
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- Have you read the contribution guide?
- Have you updated the relevant docstrings? We're using Numpy format,
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CONTRIBUTING.rst

@@ -6,8 +6,8 @@ reports, improving documentation, submitting feature requests, reviewing
 new submissions, or contributing code that can be incorporated into the
 project.
 
-Please, don't use the issue tracker for support questions. Instead use:
-`email <rectools-team@mts.ru>`__.
+For support questions please use `Telegram Channel <https://t.me/RecTools_Support>`_
+or open an issue of type `Question`
 
 Feature Requests
 ----------------
@@ -27,13 +27,36 @@ Repository as a Pull Request.
 Pull Request Process
 --------------------
 
-1. Update the README.md with details of changes to the interface,
-   including new environment variables, proper file
-   locations, and container parameters.
-2. You may merge the Pull Request in once you have the sign-off of two
-   other developers, or if you do not have permission to do that, you
-   may request the second reviewer to merge it for you. We expect to
-   have a minimum of one approval from someone else on the core team.
+#. Fork RecTools `main repository <https://github.com/MobileTeleSystems/RecTools>`_
+   on GitHub. See `this guide <https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/fork-a-repo>`_ if you have questions.
+#. Clone your fork from GitHub to your local disk.
+#. Create a virtual environment and install dependencies including all 
+   extras and development dependencies.
+
+   #. Make sure you have ``python3`` and ``poetry==1.4.0`` installed
+   #. Deactivate any active virtual environments. Deactivate conda ``base``
+      environment if applicable
+   #. Run ``make install`` command which will create a virtual env and
+      install everything that is needed with poetry. See `poetry usage details <https://python-poetry.org/docs/basic-usage/#installing-with-poetrylock>`_
+
+#. Implement your changes. Check the following after you are done:
+
+   #. Docstrings. Please ensure that all new public classes and methods
+      have docstrings. We use numpy style. Also check that examples are
+      provided
+   #. Code styling. Autoformat with ``make format``
+   #. Linters. Run checks with ``make lint``
+   #. Tests. Make sure you've covered new features with tests. Check
+      code correctness with ``make test``
+   #. Coverage. Check with ``make coverage``
+   #. Changelog. Please describe you changes in `CHANGELOG.MD <https://github.com/MobileTeleSystems/RecTools/blob/main/CHANGELOG.md>`_
+
+#. Create a pull request from your fork. See `instructions <https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/creating-a-pull-request-from-a-fork>`_
+
+
+You may merge the Pull Request in once you have the approval of one 
+of the core developers, or if you do not have permission to do that, you
+may request the a reviewer to merge it for you. 
 
 Review Process
 --------------

README.md

@@ -115,12 +115,16 @@ The table below lists recommender models that are available in RecTools.
 
 
 ## Contribution
+[Contributing guide](CONTRIBUTING.rst)
 
-To install all requirements run
+To install all requirements
+- you must have `python3` and `poetry==1.4.0` installed
+- make sure you have no active virtual environments (deactivate conda `base` if applicable)
+- run
 ```
 make install
 ```
-You must have `python3` and `poetry==1.4.0` installed.
+
 
 For autoformatting run 
 ```

docs/source/support.rst

@@ -3,4 +3,4 @@ Support
 
 .. currentmodule:: rectools
 
-If something went wrong and you can't find a way to fix it please email ``rectools-team@mts.ru``
+If something went wrong and you can't find a way to fix it please contact us at `Telegram Channel <https://t.me/RecTools_Support>`__