gistfile1.txt

[1] pry(main)> require 'sqlite3'
=> true
[2] pry(main)> require 'sequel'
=> true
[3] pry(main)> db = Sequel.sqlite
=> #<Sequel::SQLite::Database: {:adapter=>:sqlite}>
[4] pry(main)> db.create_table :example do
[4] pry(main)*   primary_key :id
[4] pry(main)*   String :test
[4] pry(main)* end  
=> nil
[5] pry(main)> db.tables
=> [:example]
[6] pry(main)> class Example < Sequel::Model
[6] pry(main)* end  
=> nil
[7] pry(main)> e = Example.new
=> #<Example @values={}>
[8] pry(main)> e.test = "Example"
NoMethodError: undefined method `test=' for #<Example @values={}>
from (pry):12:in `__pry__'

plural.rb

$ cat models.rb 
require_relative 'models/user'

Database.create_table :users do
  primary_key :id
  String :email
  String :instapaper_id
  String :name
end unless Database.table_exists? :users

$ cat models/user.rb
class User < Sequel::Model

end

$ irb          
[1] pry(main)> require './models'
=> true
[2] pry(main)> User
=> User
[3] pry(main)> u = User.new
=> #<User @values={}>
[4] pry(main)> u.name = "Fred"
NoMethodError: undefined method `name=' for #<User @values={}>
from (pry):4:in `__pry__'
[5] pry(main)> Database
=> #<Sequel::SQLite::Database: {:adapter=>:sqlite}>
[6] pry(main)> Database.tables
=> [:users]