Update README

README.md

@@ -8,14 +8,14 @@ and automatically ingest them into an appropriate Butler repository.
 Containers
 ----------
 
-Three containers are built from this repo: enqueue, ingest, and idle.
+Four containers are built from this repo: enqueue, ingest, idle, and presence.
 
 Building
 --------
 
-Pull requests will build versions of all three containers tagged with the PR's "head ref".
-If a tag (which should always be on main and prefixed with "v") is pushed, versions of all three containers with that tag's version number will be built.
-Otherwise, merges to main will result in versions of all three containers tagged with "latest".
+Pull requests will build versions of all four containers tagged with the PR's "head ref".
+If a tag (which should always be on main and prefixed with "v") is pushed, versions of all four containers with that tag's version number will be built.
+Otherwise, merges to main will result in versions of all four containers tagged with "latest".
 
 If the code in this repo has not changed but a new version of the Science Pipelines stack is needed for the ingest container, the ["On-demand ingest build" workflow](https://github.com/lsst-dm/embargo-butler/actions/workflows/build-manually.yaml) should be executed.
 It takes a ref — which should be the latest tag, not usually a branch — a rubin-env version, and the Science Pipelines release tag (e.g. `w_2023_41`).