我一直在我的rails应用程序中使用gem audited。起初我使用的是sqlite3数据库，但最近已切换到MySQL。当我尝试访问gem提供的关联时（例如：myObject.audits），我收到以下错误。
`ArgumentError: undefined class/module ActiveRecord::ConnectionAdapters::SQLite3String
from /home/david/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/psych/class_loader.rb:53:in `path2class'
from /home/david/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/psych/class_loader.rb:53:in `resolve'
from /home/david/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/psych/class_loader.rb:45:in `find'
from /home/david/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/psych/class_loader.rb:27:in `load'
from /home/david/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/psych/visitors/to_ruby.rb:360:in `resolve_class'
from /home/david/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/psych/visitors/to_ruby.rb:203:in `visit_Psych_Nodes_Mapping'
from /home/david/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/psych/visitors/visitor.rb:15:in `visit'
from /home/david/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/psych/visitors/visitor.rb:5:in `accept'
from /home/david/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/psych/visitors/to_ruby.rb:31:in `accept'
from /home/david/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/psych/visitors/to_ruby.rb:302:in `block in revive_hash'
from /home/david/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/psych/visitors/to_ruby.rb:300:in `each'
from /home/david/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/psych/visitors/to_ruby.rb:300:in `each_slice'
from /home/david/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/psych/visitors/to_ruby.rb:300:in `revive_hash'
from /home/david/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/psych/visitors/to_ruby.rb:161:in `visit_Psych_Nodes_Mapping'
from /home/david/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/psych/visitors/visitor.rb:15:in `visit'
from /home/david/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/psych/visitors/visitor.rb:5:in `accept'
... 63 levels...
from /home/david/.rvm/gems/ruby-2.1.3/gems/activerecord-4.2.0/lib/active_record/attribute_set.rb:31:in `fetch_value'
from /home/david/.rvm/gems/ruby-2.1.3/gems/activerecord-4.2.0/lib/active_record/attribute_methods/read.rb:93:in `_read_attribute'
from /home/david/.rvm/gems/ruby-2.1.3/gems/activerecord-4.2.0/lib/active_record/attribute_methods/read.rb:87:in `read_attribute'
from /home/david/.rvm/gems/ruby-2.1.3/gems/activerecord-4.2.0/lib/active_record/attribute_methods.rb:305:in `attribute_for_inspect'
from /home/david/.rvm/gems/ruby-2.1.3/gems/activerecord-4.2.0/lib/active_record/core.rb:443:in `block in inspect'
from /home/david/.rvm/gems/ruby-2.1.3/gems/activerecord-4.2.0/lib/active_record/core.rb:441:in `collect'
from /home/david/.rvm/gems/ruby-2.1.3/gems/activerecord-4.2.0/lib/active_record/core.rb:441:in `inspect'
from /home/david/.rvm/gems/ruby-2.1.3/gems/activerecord-4.2.0/lib/active_record/relation.rb:629:in `map!'
from /home/david/.rvm/gems/ruby-2.1.3/gems/activerecord-4.2.0/lib/active_record/relation.rb:629:in `inspect'
from /home/david/.rvm/gems/ruby-2.1.3/gems/railties-4.2.0/lib/rails/commands/console.rb:110:in `start'
from /home/david/.rvm/gems/ruby-2.1.3/gems/railties-4.2.0/lib/rails/commands/console.rb:9:in `start'
from /home/david/.rvm/gems/ruby-2.1.3/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:68:in `console'
from /home/david/.rvm/gems/ruby-2.1.3/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
from /home/david/.rvm/gems/ruby-2.1.3/gems/railties-4.2.0/lib/rails/commands.rb:17:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'2.1.3 :004 >`
我不确定从哪里开始调试此错误。谁能提供一些方向？谢谢！