Updated README.md w/instructions for attr_accessible (#977)
Updated README.md w/instructions for attr_accessible (#977)

included code sample & instructions for using papertrail 7.0.x  w/attr_accessible.

See https://github.com/airblade/paper_trail/issues/279 for context/discussion
airblade/paper_trail,ifeelgoods/paper_trail,ifeelgoods/paper_trail,airblade/paper_trail