title: Sequel::Model: Where the methods like create_table come from?
body: <p>I am trying to understand how Sequel works. The example below inherit from Sequel::Model and calls set_schema, create_table, etc.</p>
  
  <p>I was trying to find the documentation for these methods, but no luck on the rdoc for Sequel::Model: <a href="http://sequel.rubyforge.org/rdoc/classes/Sequel/Model.html" rel="nofollow noreferrer">http://sequel.rubyforge.org/rdoc/classes/Sequel/Model.html</a></p>
  
  <p>Where are these methods coming from and how does Sequel::Model make them available?</p>
  
  <pre><code>class Task &lt; Sequel::Model
    set_schema do
      primary_key :id
  
      varchar :title, :unique =&gt; true, :empty =&gt; false
      boolean :done, :default =&gt; false
    end
  
    create_table unless table_exists?
  
    if empty?
      create :title =&gt; 'Laundry'
      create :title =&gt; 'Wash dishes'
    end
  end
  </code></pre>