allow user to create an access token to access stf api from user settings tab.

lib/util/jwtutil.js

@@ -5,10 +5,12 @@ module.exports.encode = function(options) {
   assert.ok(options.payload, 'payload required')
   assert.ok(options.secret, 'secret required')
 
+  var expiry = options.expiry || Date.now() + 24 * 3600
+
   return jws.sign({
     header: {
       alg: 'HS256'
-    , exp: Date.now() + 24 * 3600
+    , exp: expiry
     }
   , payload: options.payload
   , secret: options.secret