si no enviamos fecha hay que poner una por defecto

app/models/post.rb

@@ -413,6 +413,7 @@ class Post
 
   def cleanup!
     things_to_arrays!
+    default_date_is_today!
     date_to_time!
     clean_content!
     slugify_title!
@@ -501,12 +502,17 @@ class Post
     @errors
   end
 
+  def default_date_is_today!
+    set_front_matter('date', Time.now) unless date
+  end
+
   def date_to_time!
     unless @front_matter.dig(:date).is_a? Time
       @front_matter['date'] = @front_matter.dig('date').try(:to_time) || Time.now
     end
   end
 
+  # XXX es necesario ahora que tenemos select2?
   def things_to_arrays!
     [:tags,:categories].each do |c|
       thing = @front_matter.dig(c.to_s)