Declare method <column>? for boolean type

* allow to use <column>? method for booleans
* declare version for activerecord gem because this code does not work
 with rails 4
fixup
loosen activerecord version, use attr_name instead access_code
Merge pull request #4 from Slashek/define-method-with-questionmark-for-boolean

Declare method <column>? for boolean type