Add CONTRIBUTING.md

CONTRIBUTING.md

+# Contributing to this project
+
+Please take a moment to review this document in order to make the contribution
+process easy and effective for everyone involved.
+
+Following these guidelines helps to communicate that you respect the time of
+the developers managing and developing this open source project. In return,
+they should reciprocate that respect in addressing your issue or assessing
+patches and features.
+
+
+## Using the issue tracker
+
+The [issue tracker](https://gitlab.insa-rennes.fr/mpcs/dfss/issues) is the preferred channel for [bug reports](#bug-reports),
+[features requests](#feature-requests) and [submitting pull requests](#pull-requests),
+but please respect the following restrictions:
+
+* Please **do not** use the issue tracker for personal support requests (use
+  [Stack Overflow](http://stackoverflow.com) or IRC).
+
+* Please **do not** derail or troll issues. Keep the discussion on topic and
+  respect the opinions of others.
+
+## Bug reports
+
+A bug is a _demonstrable problem_ that is caused by the code in the repository.
+Good bug reports are extremely helpful - thank you!
+
+Guidelines for bug reports:
+
+1. **Use the issue search** — check if the issue has already been
+   reported.
+
+2. **Check if the issue has been fixed** — try to reproduce it using the
+   latest `master` or development branch in the repository.
+
+A good bug report shouldn't leave others needing to chase you up for more
+information. Please try to be as detailed as possible in your report. What is
+your environment? What steps will reproduce the issue? What browser(s) and OS
+experience the problem? What would you expect to be the outcome? All these
+details will help people to fix any potential bugs.
+
+Example:
+
+> Short and descriptive example bug report title
+>
+> A summary of the issue and the browser/OS environment in which it occurs. If
+> suitable, include the steps required to reproduce the bug.
+>
+> 1. This is the first step
+> 2. This is the second step
+> 3. Further steps, etc.
+>
+> Any other information you want to share that is relevant to the issue being
+> reported. This might include the lines of code that you have identified as
+> causing the bug, and potential solutions (and your opinions on their
+> merits).
+
+
+## Feature requests
+
+Feature requests are welcome. But take a moment to find out whether your idea
+fits with the scope and aims of the project. It's up to *you* to make a strong
+case to convince the project's developers of the merits of this feature. Please
+provide as much detail and context as possible.
+
+Features and bugfixes are referenced and attributed in a
+[Taiga Project](https://tree.taiga.io/project/lesterpig-mpcs/kanban).
+
+## Git branches policy
+
+The `master` branch is intended to provide a *"semi-stable"* version of the dfss
+application. It means that the code shall be fully reviewed under `master`, yet
+providing the last shiny features and bugfixes.
+
+Features and bugfixes shall be developed under their own branches, and then
+merged into `master` via a *Pull request*. **Please remove feature branches after
+merge.**
+
+As a best practice, every contributor should use the following naming convention
+for feature branches:
+
+```
+Fixes    : tg_fix_<bug_description>
+Features : tg_<feature>
+
+The "tg_" prefix is referred to the corresponding Taiga.io user-story / issue / task,
+and can be ommited.
+
+Examples :
+95_fix_crypto_tests
+158_platform_https_auth
+ssl_hotfix
+```
+
+You can rebase. But, please, do it locally (when refactoring your own topic branch).
+You don't want to have contributors against you after a missed forced push.
+
+## Pull requests
+
+Good pull requests (patches, improvements, new features) are a fantastic
+help. They should remain focused in scope and avoid containing unrelated
+commits.
+
+**Please ask first** before embarking on any significant pull request (e.g.
+implementing features, refactoring code, porting to a different language),
+otherwise you risk spending a lot of time working on something that the
+project's developers might not want to merge into the project.
+
+Please adhere to the coding conventions used throughout a project (indentation,
+accurate comments, etc.) and any other requirements (tests and their coverage).
+
+Follow this process if you'd like your work considered for inclusion in the
+project:
+
+1. Fork the project, clone your fork,
+   and configure the remotes:
+
+   ```bash
+   # Clone your fork of the repo into the current directory
+   git clone https://gitlab.insa-rennes.fr/<your-username>/<repo-name>
+   # Navigate to the newly cloned directory
+   cd <repo-name>
+   # Assign the original repo to a remote called "upstream"
+   git remote add upstream https://gitlab.insa-rennes.fr/mpcs/dfss
+   ```
+
+2. If you cloned a while ago, get the latest changes from upstream:
+
+   ```bash
+   git checkout <dev-branch>
+   git pull upstream <dev-branch>
+   ```
+
+3. Create a new topic branch (off the main project development branch) to
+   contain your feature, change, or fix:
+
+   ```bash
+   git checkout -b <topic-branch-name>
+   ```
+
+4. Commit your changes in logical chunks. Please adhere to these [git commit
+   message guidelines](http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html)
+   or your code is unlikely be merged into the main project. Use Git's
+   [interactive rebase](https://help.github.com/articles/interactive-rebase)
+   feature to tidy up your commits before making them public.
+
+   You can add a `[prefix]` at the beginning of the commit message if relevant.
+
+5. Locally merge (or rebase) the upstream development branch into your topic branch:
+
+   ```bash
+   git pull [--rebase] upstream <dev-branch>
+   ```
+
+6. Push your topic branch up to your fork:
+
+   ```bash
+   git push origin <topic-branch-name>
+   ```
+
+7. Open a Pull Request with a clear title and description.
+
+**IMPORTANT**: By submitting a patch, you agree to allow the project owner to
+license your work under the same license as that used by the project.
+
+# Conduct
+
+We are committed to providing a friendly, safe and welcoming environment for
+all, regardless of gender, sexual orientation, disability, ethnicity, religion,
+or similar personal characteristic.
+
+On IRC, please avoid using overtly sexual nicknames or other nicknames that
+might detract from a friendly, safe and welcoming environment for all.
+
+Please be kind and courteous. There's no need to be mean or rude.
+Respect that people have differences of opinion and that every design or
+implementation choice carries a trade-off and numerous costs. There is seldom
+a right answer, merely an optimal answer given a set of values and
+circumstances.
+
+Please keep unstructured critique to a minimum. If you have solid ideas you
+want to experiment with, make a fork and see how it works.
+
+We will exclude you from interaction if you insult, demean or harass anyone.
+That is not welcome behaviour. We interpret the term "harassment" as
+including the definition in the
+[Citizen Code of Conduct](http://citizencodeofconduct.org/);
+if you have any lack of clarity about what might be included in that concept,
+please read their definition. In particular, we don't tolerate behavior that
+excludes people in socially marginalized groups.
+
+Likewise any spamming, trolling, flaming, baiting or other attention-stealing
+behaviour is not welcome.
+