Add CONTRIBUTING.md

CONTRIBUTING.md

@@ -0,0 +1,46 @@
+# Contribution Guide
+
+Thank you for considering contributing. Please review the guidelines below before making a contribution.
+
+## Reporting Issues
+
+Before reporting, please check if an issue with the same content already exists.
+
+### Reporting Bugs
+
+When reporting a bug, please include the following information:
+
+- Application version
+- Terminal emulator and version being used
+- Information about the git repository to reproduce the issue
+  - If possible, provide the smallest possible repository (debugging a repository with 100,000 commits is difficult)
+
+### Suggesting Features
+
+Before proposing a new feature, please review the [Goals](./README.md#goals) and [Non-Goals](./README.md#non-goals).
+
+### Terminal Emulator Compatibility
+
+If the application does not work with your terminal emulator, please check whether the terminal emulator supports the target image display protocol.
+
+For information on tested terminal emulators, refer to [Compatibility](./README.md#compatibility).
+
+We welcome contributions of information on new terminal emulators. Please share them on the [Discussions](https://github.com/lusingander/serie/discussions).
+
+## Pull Requests
+
+Creating a pull request does not necessarily require an issue. For complex problems, creating an issue beforehand might make the process smoother.
+
+### Improving the Commit Graph
+
+Improvements to the commit graph are welcome.
+
+Tests for the commit graph are conducted in [./tests/graph.rs](./tests/graph.rs).
+
+Running the tests will output images and the test repository to `./out/graph`.
+If you add new test cases, please add these images under `./tests/graph/`.
+If existing graphs are modified, overwrite the images and ensure no unexpected changes have occurred.
+
+## Additional Information
+
+If you have any questions or concerns, please use the [Discussions](https://github.com/lusingander/serie/discussions).