Update README.md

README.md

-# <application name>
+# certificates
 
-Project template for all Iron Bank container repositories.
\ No newline at end of file
+Sidecar helper for managing CA certificates
+
+## Building
+
+1. Switch to the desired versioned directory
+2. Run `./build-scripts/build.sh`
+   * Runs docker build, and takes care of setting the appropriate build args for users running locally
+
+`build-script/build.sh` is provided as an example and helpful for building locally. You can also instead call docker build and pass build-args directly.
+
+## Build Phases
+
+Some of the GitLab containers are build ontop of previous containers, building the containers in order is necessary.
+
+1. `gitlab-base` (built on `ubi` image)
+2. `certificates` (built on `gitlab-base` image)