materialize - Materializecss chips in Rails 4 doesn't save data to db -

i have problem material chips in rails (4.2.6) app. when add class chips-initial input field, can't write data field. field nil. don't understand why. field string, when field array, got same problem.

this form:

  = simple_form_for @exemple |f| .input-field   = f.input :title  .input-field   = f.label 'content'   = f.text_area :content, class: "materialize-textarea"  .input-field.chips.chips.chips-initial.chipschips-placeholder       = f.input :tags  = f.button :submit, class: 'btn btn-primary' 

this .js initial chips

 $( document ).ready(function(){    $('.chips-initial').material_chip({     data: [{       tag: 'apple',     }, {       tag: 'microsoft',     }, {       tag: 'google',     }],     placeholder: 'enter tag',     secondaryplaceholder: '+tag',   }   ) }); 

in html:

<div class="input-field chips chips chips-initial chipschips-placeholder" data-index="0" data-initialized="true"> <div class="chip">apple<i class="material-icons close">close</i></div> <div class="chip">microsoft<i class="material-icons close">close</i></div> <div class="chip">google<i class="material-icons close">close</i></div> <input id="9c3fa6b9-b134-626b-ddbb-a0a12a538eed" class="input" placeholder="enter tag"></div> <input id="9c3fa6b9-b134-626b-ddbb-a0a12a538eed" class="input" placeholder="enter tag"> 

but when create, in console:

#<example id: 3, title: "", content: "", tags: nil, place: "", date: nil, created_at: "2016-11-04 18:31:50", updated_at: "2016-11-04 18:31:50", image_file_name: nil, image_content_type: nil, image_file_size: nil, image_updated_at: nil 

i using gem 'materialize-sass'