migration integer limit option

:limit        Numeric Type    Column Size    Max value
1             tinyint           1 byte        127
2             smallint          2 bytes       32767
3             mediumint         3 byte        8388607
nil, 4, 11    int(11)           4 byte        2147483647
5..8          bigint            8 byte        9223372036854775807

class CreateTableSubjections < ActiveRecord::Migration[5.0]
  def change
    create_table :table_subjections do |t| 
      t.belongs_to :subject, index: true
      t.belongs_to :video, index: true
      t.string :title, limit: 40
      t.string :sub_title, limit: 40
      t.string :description, limit: 500
      t.integer :status, limit: 1
      t.integer :sequence, limit: 2

      t.timestamps
    end 
  end 
end