公开或私有

db/migrate/20191225035117_modify_open_or_not_for_hacks.rb

@@ -0,0 +1,5 @@
+class ModifyOpenOrNotForHacks < ActiveRecord::Migration[5.2]
+  def change
+    change_column :hacks, :open_or_not, :boolean, :default => false
+  end
+end