Mysql2::Error: Incorrect table name '': SHOW FULL FIELDS FROM ``

[denmarkmeralpis]

I got an issue when trying to save tags. Here's my model

# application_record.rb
class ApplicationRecord < ActiveRecord::Base
  act_as_taggable
end

# foo.rb
class Foo < ApplicationRecord
end

Here's what I did

# irb
foo = Foo.new
foo.tag_list = 'abc,def,ghi'
foo.save

then it raises an error

Traceback (most recent call last):
        1: from (irb):3
ActiveRecord::StatementInvalid (Mysql2::Error: Incorrect table name '': SHOW FULL FIELDS FROM ``)