Added brief LDAP documentation.

doc/config.html

@@ -2150,7 +2150,7 @@ Options Location = Main Building{a}, New Building{b}, Old Building{c}
     </p>
     
     <h2>
-      Site authentication
+      Kerberos authentication
     </h2>
     <p>
     Starting from version 2.9.0, site authentication has been implemented
@@ -2209,6 +2209,44 @@ Options Location = Main Building{a}, New Building{b}, Old Building{c}
     login if you use a Windows Domain).
     </p>
     
+    
+    <h2>
+       LDAP authentication
+    </h2>
+    <p>
+    LDAP (lightweight Directory Access Protocol) has been implemented by
+    vykozlov in a separate branch at <a href="https://github.com/vykozlov/elog-ldap">https://github.com/vykozlov/elog-ldap</a>. The code has been merged into this distribution on
+    an as-is basis. Following info has copied from the link above:</p>
+
+    <p>
+    To use LDAP authentication, do the following:
+    </p>
+    
+    <ul>
+       <li>
+          Enable LDAP authentication in the <b><code>Makefile</code></b> by setting
+          <b><code>USE_LDAP = 1</code></b>
+       </li>
+       <li>
+          Change elogd.cf to contain LDAP authentication:
+          <ul>
+            <li><b><code>Authentication = LDAP</code></b></li>
+            <li><b><code>LDAP server = ldap://example.org:389</code></b></li>
+            <li><b><code>LDAP userbase = ou=People;dc=example,dc=org</code></b></li>
+            <li><b><code>LDAP login attribute = uid</code></b></li>
+            <li><b><code>LDAP register = 1</code></b></li>
+          </ul>
+          The <code><b>login attribute</b></code> is from the DN (distinguished name), e.g.
+          uid=user,ou=People,dc=example,dc=org. The <code><b>register</b></code> flag determines
+          if LDAP users are automatically stored in the local password file, which is
+          necessary for email notifications.
+       </li>
+    </ul>
+
+    <p>
+    Please note that it is not possible to change a password in the LDAP database from within ELOG.
+    </p>
+    
     <p>
       <a name="email" id="email"></a>
     </p>