Add LDAP authentication page

auth/use-ldap-authentication.md

@@ -0,0 +1,52 @@
+---
+layout: default
+title: Use LDAP authentication
+---
+
+### Problem
+
+You want to use LDAP authentication when Node-RED users login to Node-RED editor.
+
+### Solution
+
+Install LDAP authentication module, [node-red-auth-contrib-ldap](https://www.npmjs.com/package/node-red-auth-contrib-ldap) and configure LDAP server information in settings.js.
+
+#### Example
+
+After the setup, you can use LDAP authentication when you access to Node-RED editor.
+![](/images/auth/auth-login.png)
+
+
+#### Configration
+
+(1) Install LDAP authentication module
+```
+sudo npm install -g node-red-auth-contrib-ldap
+```
+
+(2) Add LDAP server information into settings.js
+```
+vi ~/.node-red/settings.js
+```
+Add adminAuth block in module.exports block as follows.
+```
+module.exports = {
+...
+    adminAuth: require("node-red-auth-contrib-ldap").init({
+        url: "ldap://<hostname>:389",
+        dn: "uid=%username%,ou=people,o=example,c=jp"
+    }),
+...
+}
+```
+
+(3) Run Node-RED
+```
+node-red
+```
+
+### Discussion
+
+You can modify dn(distinguished name) which corresponds with your LDAP server.
+%username% is reserved word which dn string has as user name.
+