Merge pull request #8 from jcaudle/remove-deprecation-warnings

Remove call to deprecated `set_table_name`
Update to ActiveRecord 4

`verify_active_connections!` was removed for Rails 4, so this commit
removes it in favor of the delegated `clear_all_connections!`. This
change is sufficient to get the specs passing on activerecord 4, but
because the CASino gem is not yet updated for using that version I have
pointed the gemfile at an alternative version which is updated.