Add contribution guidelines

Signed-off-by: Jacob Stopak <jacob@initialcommit.io>

Author: initialcommit-io

CONTRIBUTING.md

@@ -0,0 +1,97 @@
+# Contributing to Git-Sim
+
+Thanks for checking out Git-Sim and for your interest in contributing! I hope
+that we can work together to build an incredible tool for developers to
+visualize Git commands.
+
+## Reporting bugs
+
+To report a bug you found, please open a [GitHub issue](https://github.com/initialcommit-com/git-sim/issues/new)
+and describe the error or problem in detail. Please check [existing issues](https://github.com/initialcommit-com/git-sim/issues)
+to make sure it hasn't already been reported.
+
+When submitting a new issue, it helps to include:
+
+1) The steps you took that lead to the issue
+2) Any error message(s) that you received
+3) A description of any unexpected behavior
+4) The version of Git-Sim you're running
+5) The version of Python you're running and whether it's system-level or in a virtual environment
+6) The operating system and version you're running
+
+## Suggesting enhancements or new features
+
+If you've got a cool idea for a feature that you'd like to see implemented in
+Git-Sim, we'd love to hear about it!
+
+To suggest an enhancement or new feature, please open a [GitHub issue](https://github.com/initialcommit-com/git-sim/issues/new)
+and describe your proposed idea in detail. Please include why you think this
+idea would be beneficial to the Git-Sim user base.
+
+## Your first code contribution
+
+Note: Git-Sim is a new project so these steps are not fully optimized yet, but
+they should get you going.
+
+To start contributing code to Git-Sim, you'll need to perform the following
+steps:
+
+1) Install [manim and manim dependencies for your OS](https://www.manim.community/)
+2) [Fork the Git-Sim codebase](https://github.com/initialcommit-com/git-sim/fork)
+so that you have a copy on GitHub that you can clone and work with
+3) Clone the codebase down to your local machine
+4) For the code to run locally without getting a `ModuleNotFoundError`,
+you need to remove the import prefix `git_sim.` from imports (for example
+`from git_sim_base_command import GitSimBaseCommand`) in the following files:
+
+- __main.py__
+- git_sim.py
+- git_sim_add.py
+- git_sim_branch.py
+- git_sim_cherrypick.py
+- git_sim_commit.py
+- git_sim_log.py
+- git_sim_merge.py
+- git_sim_rebase.py
+- git_sim_reset.py
+- git_sim_restore.py
+- git_sim_revert.py
+- git_sim_stash.py
+- git_sim_status.py
+- git_sim_tag.py
+
+There is probably a way around this. When I figure it out I'll update this guide.
+
+5) You can run your local Git-Sim commands from within other local repos like this:
+
+```
+$ python ~/path/to/git-sim/git_sim/__main__.py [global options] <subcommand> [subcommand options]
+```
+
+For example, you can simulate the `git add` command locally like this:
+
+```
+$ cd path/to/any/local/git/repo
+$ python ~/path/to/git-sim/git_sim/__main__.py --animate add newfile.txt
+```
+
+6) After pushing your code changes up to your fork, [submit a pull request](https://github.com/initialcommit-com/git-sim/compare) for me
+to review your code, provide feedback, and integrate it into the codebase!
+
+## Code style guide
+
+Since Git-Sim is a new project, we don't have an official code style set in
+stone. For now just try and make your new code fit in with the existing style
+you find in the codebase, and we'll update this section later if that changes.
+
+## Commit conventions
+
+We have a few simple rules for Git-Sim commit messages:
+
+1) Write commit messages in the [imperative mood](https://initialcommit.com/blog/Git-Commit-Message-Imperative-Mood)
+2) Add a signoff trailer to your commits by using the `-s` flag when you make
+your commits, like this:
+
+```
+$ git commit -sm "Fixed xyz..."
+```