Add SSO services

README.md

@@ -299,6 +299,10 @@ Please read [CONTRIBUTING](./CONTRIBUTING.md) if you wish to add software.
 * [Nano](http://https://www.nano-editor.org/) - A popular text editor, by default comes with most Linux distributions.
 * [Visual Studio Code](https://code.visualstudio.com/) - Fast, hackable, multi-platform code editor from Microsoft.
 
+### Single Sign-On (SSO)
+
+- [PWM](https://github.com/pwm-project/pwm) - An open source password self-service application for LDAP directories including SSO interfaces ([Source Code](https://github.com/pwm-project/pwm)) `Apache-2.0` `Java`
+
 ## IT Asset Management
 
 *IT Assets Management software.*