Missing FK indexes

indexes.rb

connection = ActiveRecord::Base.connection
connection.tables.each do |table|  
  columns = connection.columns(table).collect(&:name).select {|x| x.ends_with?("_id" || x.ends_with("_type"))}
  indexed_columns = connection.indexes(table).collect(&:columns).flatten.uniq
  unindexed = columns - indexed_columns
  unless unindexed.empty?
    puts "#{table}: #{unindexed.join(", ")}"
  end
end