docs: explain how to contribute to web site and code

Sponsored-by: author

1 files changed, 44 insertions, 1 deletions

diff --git a/contributing.md b/contributing.md
index 8d8980e..993e037 100644
--- a/contributing.md
+++ b/contributing.md
@@ -1,5 +1,7 @@
 [[!meta title="Contributing to Obnam"]]
 
+[[!toc]]
+
 The Obnam project welcomes contributions. If you want to help Obnam
 become better, you can. There are many ways to contribute that don't
 involve writing code.
@@ -29,6 +31,47 @@ get in touch and we may be able to arrange something.
 
 [issue tracker]: https://gitlab.com/larswirzenius/obnam/-/issues
 
+# Set up to change the web site
+
+To contribute a change to the web site, you set up like this:
+
+* Fork the project.
+  - you will need your own account on gitlab.com for this
+* Clone the code from your fork.
+* Make a new git branch and start making changes.
+* Commit everything.
+* Push your changes back to your fork.
+* Make a merge request from your fork to the main project.
+
+You can, if you want to, test your changes by building a local copy of
+the website, but that's not required.
+
+# Set up to change the code
+
+If you want to make a contribution by changing the code, you can set
+up an environment following these steps:
+
+* Install the [Rust][] language toolchain, using [rustup][].
+  - using a toolchain packaged for, so, Debian, may also work, but may
+    be old
+* Install any other build dependencies, as described in the [README][]
+  and [debian/control] files.
+* Run `./check` to make sure everything works.
+* Fork the project.
+  - you will need your own account on gitlab.com for this
+* Clone the code from your fork.
+* Make a new git branch and start making changes.
+  - make sure `./check` works with your changes
+* Commit everything.
+* Push your changes back to your fork.
+* Make a merge request from your fork to the main project.
+
+[Rust]: https://www.rust-lang.org/
+[rustup]: https://www.rust-lang.org/tools/install
+[README]: https://gitlab.com/obnam/obnam/-/blob/main/README.md
+[debian/control]: https://gitlab.com/obnam/obnam/-/blob/main/debian/control
+[gitlab]: https://gitlab.com/obnam/obnam/
+
 # Getting Obnam to change so you can do what you want to do
 
 Sometimes it happens you want Obnam to do something that it doesn't
@@ -82,7 +125,7 @@ place:
   be able to comment.
 * Lars may update the MR based on feedback, applying his best
   judgment.
-  
+
 Typical values for N will be:
 
 * 0 for typo fixes and similar low-impact changes, or fixes to