Support LDAP auth

Related-PROD:20906

Change-Id: Ibc4401af795c3ac4a567531ffc62944112864b8a
diff --git a/README.rst b/README.rst
index c173d80..c97d20b 100644
--- a/README.rst
+++ b/README.rst
@@ -75,7 +75,21 @@
           user: gerrit
           password: ${_param:postgresql_gerrit_password}
           pool_limit: 250
-          pool_max_idle: 16 
+          pool_max_idle: 16
+
+
+Gerrit LDAP authentification
+
+.. code-block:: yaml
+
+    gerrit:
+      server:
+        auth:
+          engine: LDAP
+          ldap_server: ldap://ldap.mycompany.net
+          ldap_account_base: dc=company,dc=net
+          ldap_group_base: ou=Groups,dc=company,dc=net
+
 
 Gerrit change auto abandon
 
diff --git a/gerrit/files/gerrit.config b/gerrit/files/gerrit.config
index e720dd9..d20660c 100644
--- a/gerrit/files/gerrit.config
+++ b/gerrit/files/gerrit.config
@@ -53,6 +53,14 @@
     openIdSsoUrl = {{ server.auth.openid_sso_url }}
     {%- endif %}
 
+{%- if server.auth.engine == 'LDAP' %}
+[ldap]
+    server = {{ server.auth.ldap_server }}
+    accountBase = {{ server.auth.ldap_account_base }}
+    accountPattern = uid=${username}
+    groupBase = {{ server.auth.ldap_group_base }}
+{%- endif %}
+
 [sendemail]
     {%- if server.mail is defined %}
     smtpServer = {{ server.mail.host }}