Uncaught TypeError: $(...).tokenInput is not a function

I follow

http://ift.tt/MRKOSx

and done each and every thing according to this but when it gives me that error.

Uncaught TypeError: $(...).tokenInput is not a function

(anonymous function) @ products.js?body=1:36jQuery.Callbacks.fire @ application.js?body=1:3149jQuery.Callbacks.self.fireWith @ application.js?body=1:3261jQuery.extend.ready @ application.js?body=1:3473completed @ application.js?body=1:3504

My jquery code is

$(function() {

$("#textarea1").tokenInput("/products.json", {

crossDomain: false,

theme: "facebook"

});

}); Rails version is Rails 4.2.4 and ruby version is ruby 2.2.1