Has many to many checkboxes won't save Rails 4

Question

I've tried making my has and belongs to many relation to work, following the Rails guides and everything I could find online, but they just wont show up.. When I save my form its only INSERTS into the Pin model, it doesn't insert any relations. If I add the relation manually via terminal like so:

p = Pin.new
p.minors = [1,2]
p.save

It works, but my form which looks like this (iam using rails 4, so collections yay) it doesn't save the relations (it saves the pin just fine)

new.html.erb

  <%= collection_check_boxes(:minor_ids, :minor_ids, Minor.all, :id, :name) %>
  <%= collection_check_boxes(:competence_ids, :competence_ids, Competence.all, :id, :name) %>

pinscontroller.rb

class PinsController < ApplicationController

 def create
  @pin = Pin.new(pin_params)
  @pin.user_id = current_user.id

  if @pin.save
    redirect_to pin_path(@pin)
  end
 end

def new
 @pin = Pin.new()
end

def show
 @pin = Pin.find(params[:id])
end


private
def pin_params
 params.require(:pin).permit(:title, :name, :url, { :minor_ids => [] }, { :competence_ids => [] },)
end

end

and my model Pin.rb

 class Pin < ActiveRecord::Base
belongs_to :user
has_and_belongs_to_many :minors
has_and_belongs_to_many :competences
 end

Minor.rb

 class Minor < ActiveRecord::Base
has_and_belongs_to_many :pins
 end

Competence.rb

 class Competence < ActiveRecord::Base
  has_and_belongs_to_many :pins
 end

pin/show.html.erb

This is the way I try to check if the relations came through. They all come back empty and 0, except for the ones I did through console.

<%=  @pin.minors.count.inspect %>
<%=  @pin.competences.count.inspect %>

<% if !@pin.minors.empty? %>
<%= @pin.minors.each do |minor| %>
  <%= minor.name %>
<% end %>
<% end %>

<% if !@pin.competences.empty? %>
<%= @pin.competences.each do |comp| %>
  <%= comp.name %>
<% end %>
<% end %>

Schema.rb

create_table "competences", force: true do |t|
 t.string   "name"
 t.datetime "created_at"
 t.datetime "updated_at"
 t.integer  "pin_id"
end

create_table "competences_pins", force: true do |t|
 t.integer  "pin_id"
 t.integer  "competence_id"
 t.datetime "created_at"
 t.datetime "updated_at"
end

create_table "minors", force: true do |t|
 t.string   "name"
 t.datetime "created_at"
 t.datetime "updated_at"
 t.integer  "pin_id"
end

create_table "minors_pins", force: true do |t|
 t.integer  "pin_id"
 t.integer  "minor_id"
 t.datetime "created_at"
 t.datetime "updated_at"
end

create_table "pins", force: true do |t|
 t.string   "title"
 t.string   "url"
 t.string   "image"
 t.string   "username"
 t.integer  "views"
 t.datetime "created_at"
 t.datetime "updated_at"
 t.integer  "user_id"
end

So, am I missing a step? So far i've tried everything but the minors_pins and the competences_pins tables remain empty, all the help and insight I can get!

Answer 1

I fixed this by adding @minors = Minor.all in the pins controller in the new method. And by replacing <%= collection_check_boxes(:minor_ids, :minor_ids, Minor.all, :id, :name) %> with <%= f.collection_check_boxes(:minor_ids, @minors, :id,:name)%>