Rails 4 nested attributes multiple records when updating

Rails
1

I’m stuck and i don’t know why it is not working right. I have a model
lesson wich has many sublessons. When i update the lesson rails update
properly the lesson attributes but is creating another sublessons
records instead of just updating it.

Here is my code

View Form:

<%= form_for @lesson do |f| %> <%= f.label :lesson_name, "Lesson title" %> <%= f.text_field :lesson_name, class: "form-control" %> <%= f.label :lesson_icon, "Choise icon" %> <%= f.select "lesson_icon", options_for_select([ "ico03", "ico04","ico05","ico06" ])%>
<%= f.fields_for :sublessons do |sublesson_a| %> 
       <%= sublesson_a.label :sublesson_name, "Subtitle 1" %></br>
       <%= sublesson_a.text_field :sublesson_name, class:

“form-control” %>
<%= sublesson_a.label :sublesson_content, “Content” %>
<%=sublesson_a.text_area ‘sublesson_content’, rows: 3, class:
‘form-control’%>
<%= sublesson_a.label :sublesson_video_link, “Video link”
%>

<%= sublesson_a.text_field :sublesson_video_link, class:
“form-control” %>
<%end%>



<%= f.submit “Submit”, class: “btn btn-primary” %>

<% end %>

lesson model
class Lesson < ActiveRecord::Base
has_many :sublessons, :dependent => :destroy
accepts_nested_attributes_for :sublessons, :reject_if => :all_blank
end
sublesson model

class Sublesson < ActiveRecord::Base
belongs_to :lesson, :foreign_key => “lesson_id”
validates :sublesson_name, presence: true
validates :sublesson_content ,presence: true
end

lesson controller

def update
@lesson = Lesson.find(params[:id])
@[email protected]
if @lesson.update(lesson_params)
flash[:notice] = “Lesson updated”
redirect_to lessons_show_url
else
flash[:notice] = “Error”
redirect_to lessons_show_url
end
end

def edit
@lesson = Lesson.find(params[:id])
@[email protected]
end

def lesson_params
params.require(:lesson).permit(:lesson_name, :lesson_icon,
sublessons_attributes:[:sublesson_id, :sublesson_name,
:sublesson_content, :sublesson_video_link])
end