title: rake db:migrate UNEXPECTED error
body: <p>Hello pls help with an unexpected error when I run my rails app. 
  <strong>rake db:migrate</strong>
  then there is an error</p>
  
  <pre><code>CreateTodoItems: migrating ==================================
  -- create_table(:todo_items)
  rake aborted!
  StandardError: An error has occurred, this and all later migrations canceled:
  
  undefined method `reference' for #&lt;ActiveRecord::ConnectionAdapters::TableDefinition:0x007f9d9c981ed0&gt;/Users/chenziwang/odot/db/migrate/20150421184553_create_todo_items.rb:4:in `block in change'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/connection_adapters/abstract/schema_statements.rb:202:in `create_table'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:662:in `block in method_missing'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:632:in `block in say_with_time'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:632:in `say_with_time'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:652:in `method_missing'
  /Users/chenziwang/odot/db/migrate/20150421184553_create_todo_items.rb:3:in `change'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:606:in `exec_migration'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:590:in `block (2 levels) in migrate'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:589:in `block in migrate'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:292:in `with_connection'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:588:in `migrate'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:765:in `migrate'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:995:in `block in execute_migration_in_transaction'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:1041:in `block in ddl_transaction'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `block in transaction'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/connection_adapters/abstract/transaction.rb:188:in `within_new_transaction'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `transaction'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/transactions.rb:220:in `transaction'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:1041:in `ddl_transaction'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:994:in `execute_migration_in_transaction'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:956:in `block in migrate'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:952:in `each'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:952:in `migrate'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:820:in `up'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/migration.rb:798:in `migrate'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/tasks/database_tasks.rb:137:in `migrate'
  /Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.1/lib/active_record/railties/databases.rake:44:in `block (2 levels) in &lt;top (required)&gt;'
  Tasks: TOP =&gt; db:migrate
  (See full trace by running task with --trace)
  </code></pre>
  
  <p>my migrate files are:</p>
  
  <pre><code>class CreateTodoLists &lt; ActiveRecord::Migration
    def change
      create_table :todo_lists do |t|
        t.string :title
        t.text :description
  
        t.timestamps null: false
      end
    end
  end
  </code></pre>
  
  <p>Another file is </p>
  
  <pre><code>class CreateTodoItems &lt; ActiveRecord::Migration
    def change
      create_table :todo_items do |t|
        t.reference :todo_list
        t.string :content
  
        t.timestamps null: false
      end
    end
  end
  </code></pre>