Update installation.md to add SSO configuration file evolution

Schematron-Validator/installation.md

@@ -82,6 +82,26 @@ Be sure the directory can be read/written by JBoss.
 sudo chmod -R 775 /opt/SchematronValidator_prod
 sudo chown -R jboss:jboss-admin /opt/SchematronValidator_prod
 ```
+
+## SSO
+This application read the configuration of the SSO in a file located in `/opt/gazelle/cas`. We need to create this folder and the configuration file `SchematronValidator.properties`.
+
+```
+ mkdir /opt/gazelle/cas
+ touch /opt/gazelle/cas/SchematronValidator.properties
+ chown -R jboss:jboss-admin /opt/gazelle/cas
+ chmod -R g+w /opt/gazelle/cas
+```
+
+Here is a sample of the content of the property file. Please replace __stretch.localdomain__ with the __FQDN__ of your server.
+
+```
+casServerUrlPrefix=https://stretch.localdomain/sso
+casServerLoginUrl=https://stretch.localdomain/sso/login
+casLogoutUrl=https://stretch.localdomain/sso/logout
+service=https://stretch.localdomain/SchematronValidator
+```
+
 # Update from a previous version
 
 1. Download the new **ear** and its associated update SQL script from our [*Nexus Repository Manager*](https://gazelle.ihe.net/nexus/index.html#nexus-search;quick%7ESchematronValidator-ear) (search for **SchematronValidator-X.X.X.ear** and **SchematronValidator-X.X.X-sql.zip**). Not each version has an update sql to execute.