Use tasks api for external ldap syncer

src/taskworker.js

@@ -9,6 +9,7 @@ var apptask = require('./apptask.js'),
     database = require('./database.js'),
     debug = require('debug')('box:taskworker'),
     domains = require('./domains.js'),
+    externalldap = require('./externalldap.js'),
     reverseProxy = require('./reverseproxy.js'),
     settings = require('./settings.js'),
     tasks = require('./tasks.js'),
@@ -23,6 +24,7 @@ const TASKS = { // indexed by task type
     renewcerts: reverseProxy.renewCerts,
     prepareDashboardDomain: domains.prepareDashboardDomain,
     cleanBackups: backups.cleanup,
+    syncExternalLdap: externalldap.sync,
 
     _identity: (arg, progressCallback, callback) => callback(null, arg),
     _error: (arg, progressCallback, callback) => callback(new Error(`Failed for arg: ${arg}`)),