better README (#5)

README.md

@@ -1,14 +1,24 @@
 # dependencies
 
-a central repo for managing and vendoring third party dependencies for all comma projects.
+a central repo for managing and [vendoring](https://htmx.org/essays/vendoring/) third party dependencies for all comma projects.
 
-all of our projects are python projects, so each of these gets packaged as a pip project.
+since all our projects are Python, we wrap each vendored dependency as a pip package. `git clone` and `uv sync` is all you need.
 
-this vendoring serves a few goals:
+motivations for this approach
-- all dependencies are centrally managed here
+- `apt-get` is slow
-- we can slim them down to only what we need
+- `apt-get` updates its packages on a schedule we don't control
-- all platforms get the same versions installed
+- `apt-get` package versions don't match `brew` versions
-- tighter control of distribution for fast installs (e.g. Ubuntu's `apt-get` is slow)
+- `apt-get` doesn't come with Arch Linux
+- `apt-get` doesn't always have the exact package we need
+- `apt-get` packages are often bloated
+
+<!--
+this critically adds friction to adding dependencies to our project
+- `apt-get` installing a package is easy. is it 1MB, 10MB, or 100MB? no idea.
+- `apt-get` installing a package is much easier than adding it here. how much do you want it?
+-->
+
+`uv`, as opposed to `apt-get`, `brew`, and friends, is fast and already used in our projects.
 
 we target the following platforms:
 - Linux x86_64
@@ -16,3 +26,30 @@ we target the following platforms:
 - Darwin aarch64 (Apple Silicon)
 
 contributions welcome for other platforms!
+
+## packages
+
+| package           | description                                                              |
+|-------------------|--------------------------------------------------------------------------|
+| gcc-arm-none-eabi | builds [panda](https://github.com/commaai/panda) firmware for STM32 MCUs |
+| capnproto         | message serialization for openpilot                                      |
+| ffmpeg            | video encode and decode for openpilot                                    |
+| git-lfs           | for tracking large files in openpilot                                    |
+| zeromq            | bridging the openpilot IPC between different hosts                       |
+
+## usage
+
+```python
+dependencies = [
+  "capnproto @ git+https://github.com/commaai/dependencies.git@releases#subdirectory=capnproto",
+  "ffmpeg @ git+https://github.com/commaai/dependencies.git@releases#subdirectory=ffmpeg",
+]
+```
+
+## workflow
+
+to add a new package:
+* start a new top-level directory as a new package
+* `./test.sh` tests the building of all packages
+*  on pushes to `master`, wheels are built for our target platforms and pushed to a GitHub release
+*  the `releases` branch contains shim packages that allow pointing to a git branch and always getting the appropriate wheel for your platform