Migration
add_column :table_name, :column_name, :decimal, default: 0, precision: 15, scale: 10
add_column :table_name, :column_name, :jsonb, default: {}, null: false
add_column :table_name, :column_name, :string, array: true, default: []
add_foreign_key :table_name, :table_name
add_foreign_key :table_name, :table_name, column: :column_name, name: :index_table_name_on_column_name