Add ActiveModel module instance methods to prohibited_methods list

[fixes #3620]
Validate method? and method= on create field

We need to validate if the name of the field collide with methods name
such foo? or foo= .

[fixes #3620]
Changelog entry for #3620
Move Changelog entry.
Better Changelog for Mass assignment security.

[fixes #3665]
Use rspec 3 final
Set rc1 version
Better test example [skip ci]