only run ci on pull request and add docs to readme [CI SKIP]

.drone.yml

@@ -30,5 +30,4 @@ steps:
 
 trigger:
   event:
-  - push
   - pull_request

README.md

@@ -45,6 +45,17 @@ _Better [Scuttlebutt](https://scuttlebutt.nz) cloud infrastructure as a hardware
  - [peach-patterns](https://github.com/peachcloud/peach-patterns) - Pattern library for the PeachCloud UI design system
  - [peach-web](https://github.com/peachcloud/peach-web) - A web interface for monitoring and interacting with the PeachCloud device
 
+## Continuous Integration
+
+[Drone CI](https://docs.drone.io/) is used to provide continuous integration for this workspace. The configuration file can be found in `.drone.yml` in the root of this repository. It is currently configured to run `cargo fmt`, `cargo clippy`, `cargo test` and `cargo build` on every `pull request` event. The pipeline runs on the AMD64 Debian Buster image from the official Rust Docker image repository.
+
+The status of the current and previous CI builds can be viewed via the [Drone CI Build UI](https://build.coopcloud.tech/PeachCloud/peach-workspace) (kindly hosted by Co-op Cloud).
+
+Adding `[CI SKIP]` to the end of a commit message results in the CI checks being skipped for the next event. For example:
+
+`git commit -m "update readme [CI SKIP]"`
+`git push origin main`
+
 ## Developer Diaries
 
 - [@ahdinosaur](https://github.com/ahdinosaur): `@6ilZq3kN0F+dXFHAPjAwMm87JEb/VdB+LC9eIMW3sa0=.ed25519`