📝(contributing) add changelog part in contributing

We add a new section in the CONTRIBUTING.md file
to explain how to update the CHANGELOG.md file.
We improve the pull request section as well.

Author: AntoLC

CONTRIBUTING.md

@@ -20,7 +20,7 @@ All commit messages must adhere to the following format:
 
 `<gitmoji>(type) title description`
 
-*   **<gitmoji>**: Use a gitmoji to represent the purpose of the commit. For example, ✨ for adding a new feature or 🔥 for removing something, see the list here: <https://gitmoji.dev/>.
+*   <**gitmoji**>: Use a gitmoji to represent the purpose of the commit. For example, ✨ for adding a new feature or 🔥 for removing something, see the list here: <https://gitmoji.dev/>.
 *   **(type)**: Describe the type of change. Common types include `backend`, `frontend`, `CI`, `docker` etc...
 *   **title**: A short, descriptive title for the change, starting with a lowercase character.
 *   **description**: Include additional details about what was changed and why.
@@ -33,9 +33,28 @@ All commit messages must adhere to the following format:
 Implemented login and signup features, and integrated OAuth2 for social login.
 ```
 
+## Changelog Update
+
+Please add a line to the changelog describing your development. The changelog entry should include a brief summary of the changes, this helps in tracking changes effectively and keeping everyone informed. We usually include the title of the pull request, followed by the pull request ID to finish the log entry. The changelog line should be less than 80 characters in total.
+
+### Example Changelog Message
+```
+## [Unreleased]
+
+## Added
+
+- ✨(frontend) add AI to the project #321
+```
+
 ## Pull Requests
 
-It is nice to add information about the purpose of the pull request to help reviewers understand the context and intent of the changes.
+It is nice to add information about the purpose of the pull request to help reviewers understand the context and intent of the changes. If you can, add some pictures or a small video to show the changes.
+
+### Don't forget to: 
+- check your commits
+- check the linting: `make lint && make frontend-lint`
+- check the tests: `make test`
+- add a changelog entry
 
 Once all the required tests have passed, you can request a review from the project maintainers.