You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: 20171120145900_create_collection_numbers.rb
    path of file: ./repos/mushroom-observer/db/migrate
    
    the code of the file until where you have to start completion: class CreateCollectionNumbers < ActiveRecord::Migration
  def up
    create_table :collection_numbers, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8" do |t|
      t.timestamps
      t.integer  :user_id
 
    
  def up
    create_table :collection_numbers, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8" do |t|
      t.timestamps
      t.integer  :user_id
      t.string   :name
      t.string   :number
    end

    create_table :collection_numbers_observations, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8", id: false, force: true do |t|
      t.integer  :collection_number_id
      t.integer  :observation_id
    end
  end