Ensure proper permissions are set for gravity.db after creation.

Signed-off-by: DL6ER <dl6er@dl6er.de>

automated install/basic-install.sh

@@ -1908,6 +1908,9 @@ installPihole() {
             chmod a+rx /var/www/html
             # Give pihole access to the Web server group
             usermod -a -G ${LIGHTTPD_GROUP} pihole
+            # Give lighttpd access to the pihole group so the web interface can
+            # manage the gravity.db database
+            usermod -a -G pihole ${LIGHTTPD_USER}
             # If the lighttpd command is executable,
             if is_command lighty-enable-mod ; then
                 # enable fastcgi and fastcgi-php