ruby - I can't figure out why I'm getting this error in rails app: First argument in form cannot contain nil or be empty error -

ok i've been trying figure out awhile... wan´t render partial in views/users/show.html.erb

this form code in partial want rendered

<%= form_for @addon, :html => {:class => "form-horizontal center"} |f| %>   <div class="form-group">     <%= f.label :addon_1, "1.addon:", class: "col-md-4 control-label" %>     <div class="col-md-8">       <%= f.text_field :addon_1, class: "form-control" %>     </div>   </div>   <div class="form-group">     <%= f.label :addon_2, "2.addon:", class: "col-md-4 control-label" %>     <div class="col-md-8">       <%= f.text_field :addon_2, class: "form-control" %>     </div>   </div>    <div class="form-group">     <%= f.label :addon_3, "3.addon:", class: "col-md-4 control-label" %>     <div class="col-md-8">       <%= f.text_field :addon_3, class: "form-control" %>     </div>   </div>   <%= f.submit "submit", class: "btn btn-default btn-primary" %>   

i have addon.rb model , user.rbmodel

this addon.rb model

class addon < activerecord::base    belongs_to :user end 

and user.rbmodel

class user < activerecord::base  has_many :addons end 

and in users_controller.rb have, in showaction

def show   #@addon = current_user.addons.build    @addons = current_user.addons end 

i've tried both use @addons , @addon both gives errors.

if use @addons rails gives error first argument in form cannot contain nil or empty

and if try use @addon rails gives error :unknown attribute 'user_id' addon

am missing here, can't see why shouldn't work, can please advise.

i think not logged in, there no current_user & @addon.