Adds contributing guidelines

Introduces a CONTRIBUTING.MD file to provide guidelines for
contributing to the project, including prerequisites, setup
instructions, pull request workflow, code style, and building
instructions.

xd

returned back

patch

CONTRIBUTING.md

@@ -0,0 +1,32 @@
+## 🤝 Contributing to OMath or other Orange's Projects
+
+### ❕ Prerequisites
+
+- A working up-to-date OMath installation
+- C++ knowledge
+- Git knowledge
+- Ability to ask for help (Feel free to create empty pull-request or PM a maintainer
+  in [Telegram](https://t.me/orange_cpp))
+
+### ⏬ Setting up OMath
+
+Please read INSTALL.md file in repository
+
+### 🔀 Pull requests and Branches
+
+In order to send code back to the official OMath repository, you must first create a copy of OMath on your github
+account ([fork](https://help.github.com/articles/creating-a-pull-request-from-a-fork/)) and
+then [create a pull request](https://help.github.com/articles/creating-a-pull-request-from-a-fork/) back to OMath.
+
+OMath developement is performed on multiple branches. Changes are then pull requested into master. By default, changes
+merged into master will not roll out to stable build users unless the `stable` tag is updated.
+
+### 📜 Code-Style
+
+The orange code-style can be found in `.clang-format`.
+
+### 📦 Building
+
+OMath has already created the  `cmake-build` and `out` directories where cmake/bin files are located. By default, you
+can build OMath by running `cmake --build cmake-build/build/windows-release --target omath -j 6` in the source
+directory.