s1.rb

# coding: utf-8
require 'rubygems'
require 'sequel'

## connect to database.
Sequel::Model.plugin(:schema)
DB = Sequel.sqlite('database.sqlite3')

## create a table.
class Person < Sequel::Model
  unless table_exists?
    set_schema do
      primary_key :id
      string  :name
      integer :age
    end

    create_table
  end
end

Person.create(:name => 'Pamyu Pamyu', :age => 19)