add instructions for testing webroot values in docker dev environments

CONTRIBUTING.md

@@ -81,6 +81,7 @@ The OpenEMR development docker environment has a very rich advanced feature set.
 16. [Place/remove testing sql ssl certificate and testing sql ssl client key/cert](#dev_tools_ssl)
 17. [CouchDB integration](#dev_tools_couchdb)
 18. [LDAP integration](#dev_tools_ldap)
+19. [Test webroot value](#dev_tools_webroot)
 
 ---
 
@@ -395,6 +396,17 @@ The OpenEMR development docker environment has a very rich advanced feature set.
           ```sh
           docker exec -i $(docker ps | grep _openemr | cut -f 1 -d " ") sh -c '/root/devtools ldap-ssl-client-off'
           ```
+19. <a name="dev_tools_webroot"></a>Test webroot value.
+    - The default setup of the docker development environments are with a blank webroot, however, it is a good idea to also test with a webroot setting. There is an option to set the webroot to openemr.
+    - Note this dev tool requires the use of the openemr-cmd script, which is discussed above and can find instructions to install and use openemr-cmd script at [install openemr-cmd](https://github.com/openemr/openemr-devops/tree/master/utilities/openemr-cmd).
+    - Set webroot to blank:
+      ```sh
+      openemr-cmd change-webroot-blank
+      ```
+    - Set webroot to `openemr`:
+      ```sh
+      openemr-cmd change-webroot-openemr
+      ```
 
 ### Non-docker Use