Turns out RUN needs to run before the COPY.

The `apt-get` upgrade recommendation per the documentation should always run before adding any other code.

Author: Rudd-O

docs/install/containers/images/backend.md

@@ -326,8 +326,8 @@ docker run -p 8080:8080 myproject:latest start
 In the directory containing your `Dockerfile`, create a folder `etc/zope.conf.d`.
 Add your `zope.conf` configuration fragments there.
 
-Now add the following to your `Dockerfile`, before any `RUN`, `CMD` or `ENTRYPOINT`
-stanzas it may have, and after the `FROM` stanza:
+Now add the following to your `Dockerfile`, before any `CMD` or `ENTRYPOINT`
+stanzas it may have, and after the `FROM` and any `RUN` stanzas:
 
 ```Dockerfile
 COPY /etc/zope.conf.d/*.conf /app/etc/zope.conf.d/
@@ -342,8 +342,8 @@ In the directory containing your `Dockerfile`, create a folder `etc/package-incl
 Add your ZCML configuration fragments (named `*-meta.zcml`, `*-configure.zcml`,
 `*-overrides.zcml`) as files in that folder.
 
-Now add the following to your `Dockerfile`, before any `RUN`, `CMD` or `ENTRYPOINT`
-stanzas it may have, and after the `FROM` stanza:
+Now add the following to your `Dockerfile`, before any `CMD` or `ENTRYPOINT`
+stanzas it may have, and after the `FROM` and any `RUN` stanzas:
 
 ```Dockerfile
 COPY /etc/package-includes/*.zcml /app/etc/package-includes/