adds ballot_lines counter to investments

db/migrate/20170428111355_add_ballot_line_count_to_investments.rb

@@ -0,0 +1,5 @@
+class AddBallotLineCountToInvestments < ActiveRecord::Migration
+  def change
+    add_column :budget_investments, :ballot_lines_count, :integer, default: 0
+  end
+end