removes heading reference in ballot

heading info is stored per group in ballot_lines

app/models/budget/ballot.rb

@@ -2,7 +2,6 @@ class Budget
   class Ballot < ActiveRecord::Base
     belongs_to :user
     belongs_to :budget
-    belongs_to :heading
 
     has_many :lines, dependent: :destroy
     has_many :investments, through: :lines

app/models/budget/investment.rb

@@ -49,9 +49,6 @@ class Budget
 
     scope :for_render,             -> { includes(heading: :geozone) }
 
-    scope :with_heading,           -> { where.not(heading_id: nil) }
-    scope :no_heading,             -> { where(heading_id: nil) }
-
     before_save :calculate_confidence_score
     before_validation :set_responsible_name
 

db/migrate/20160614091639_remove_heading_id_from_ballot.rb

@@ -0,0 +1,5 @@
+class RemoveHeadingIdFromBallot < ActiveRecord::Migration
+  def change
+    remove_column :budget_ballots, :heading_id, :integer
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20160610094658) do
+ActiveRecord::Schema.define(version: 20160614091639) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -96,11 +96,8 @@ ActiveRecord::Schema.define(version: 20160610094658) do
     t.integer  "budget_id"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.integer  "heading_id"
   end
 
-  add_index "budget_ballots", ["heading_id"], name: "index_budget_ballots_on_heading_id", using: :btree
-
   create_table "budget_groups", force: :cascade do |t|
     t.integer "budget_id"
     t.string  "name",      limit: 50