add FreeIPA to LDAP section

README.md

@@ -272,6 +272,7 @@
 
 * [389 Directory Server](http://port389.org) - Developed by Red Hat.
 * [Apache Directory Server](http://directory.apache.org/) - Apache Software Foundation project written in Java.
+* [FreeIPA](http://www.freeipa.org/) - security management solution, can manage LDAP,KRB,DNS, sudo, and more
 * [Fusion Directory](http://www.fusiondirectory.org) - Improve the Management of the services and the company directory based on OpenLDAP.
 * [OpenDJ](http://opendj.forgerock.org/) - Fork of OpenDS.
 * [OpenDS](https://opends.java.net/) - Another directory server written in Java.