README: Add guidelines for submitting patches.

README.md

@@ -10,3 +10,48 @@ macros, which I haven't figured out how to get working with Typed
 Racket yet.
 
 Contributions, comments, bug reports, etc. are very welcome!
+
+## Submitting patches
+
+Start by checking out this repository:
+
+```
+git clone https://git.marvid.fr/scolobb/typed-graph.git
+cd typed-graph
+```
+
+Start a new branch `my-contribution` for you contribution:
+
+```
+git checkout -b my-contribution
+```
+
+Hack hack hack, do a couple commits, maybe take a look at a list of
+the commits your branch `my-contribution` contains:
+
+```
+git log --pretty=oneline master..my-contribution
+```
+
+Now create one patch file for every commit added to branch
+`my-contribution`, which is new with respect to `master`:
+
+```
+git format-patch master
+```
+
+This should produce one patch file for commit,
+e.g. `0001-Commit-1.patch`, `0002-Commit-2.patch`, etc.  Send all of
+these files to me to `scolobb` at `marvid.fr`, or to any other address
+you think you can contact me at.  I will give you feedback and we will
+work together towards getting your changes in, which is a fancy way of
+saying that I will probably take in your changes without too much
+hassle if they follow some very basic style guidelines.  Speaking of
+which:
+
+## Style guidelines
+
+When submitting changes, try to make them as similar as possible in
+style to the existing code, which approximately follows the style used
+across the Racket code base. If you use Emacs with Racket Mode or
+DrRacket, you should be fine with default settings.