Update README

Dockerfile

 # A FROM line must be present but is ignored. It will be overridden by the --image-stream parameter in the buildConfig
 FROM centos/php-73-centos7
+
 # Temporarily switch to root user to install packages
 USER root
+
 # Install PHP dependencies
 RUN yum install -y \
-    epel-release
-RUN yum install -y \
-    php-imap
+-    epel-release
 
-# Fix php-imap location
-RUN cp /etc/php.d/imap.ini /etc/opt/rh/rh-php73/php.d/20-imap.ini
-RUN cp /etc/php.d/imap.ini \
-    /opt/rh/rh-php73/register.content/etc/opt/rh/rh-php73/php.d/20-imap.ini
-RUN cp /usr/lib64/php/modules/imap.so \
-    /opt/rh/rh-php73/root/usr/lib64/php/modules/imap.so
+RUN yum install -y \
+  rh-php73-php-imap
 
 # Make sure the final image runs as unprivileged user
 USER 1001

README.md

@@ -8,7 +8,7 @@ We need to add some missing packages so we follow the procedure at
 It is just using the `centos/php-73-centos7` S2I builder and checking
 out Z-Push from a submodule.
 
-## Create the custom builder
+## Create the custom builder (first time only)
 
 This is using the top-level `Dockerfile`.
 
@@ -26,11 +26,7 @@ oc new-build \
   --strategy=docker https://gitlab.cern.ch/mail/zpush-openshift.git
 ```
 
-## Update the custom builder
-
-TODO
-
-## Create an app based on the custom builder
+## Create an app based on the custom builder (first time only)
 
 For `test`:
 ```
@@ -46,6 +42,20 @@ oc new-app \
   --context-dir=Z-Push/src --name zpush
 ```
 
+## Re-build the custom builder
+
+```
+oc start-build zpush-builder
+oc logs -f bc/zpush-builder
+```
+
+## Re-build the app image
+
+```
+oc start-build zpush
+oc logs -f bc/zpush
+```
+
 ## DC configuration
 
 A few volumes are needed: