Don't warn on link_to in Rails > 3.0
Don't warn on link_to in Rails > 3.0

closes #32

jeffyip/brakeman,spcoder/brakeman,dfens/brakeman,htdc/brakeman,liqites/brakeman,github/brakeman,dfens/brakeman,github/brakeman,liqites/brakeman,masarakki/brakeman,PragTob/brakeman,lee-leon/brakeman,kbrock/brakeman,codeclimate/brakeman-deprecated,jlecour/brakeman,jlecour/brakeman,oreoshake/brakeman,htdc/brakeman,bf4/brakeman,jlecour/brakeman,spcoder/brakeman,masarakki/brakeman,jakeatwork/brakeman,PragTob/brakeman,cheerfulstoic/brakeman,jeffyip/brakeman,jakeatwork/brakeman,kbrock/brakeman,cheerfulstoic/brakeman,codeclimate/brakeman-deprecated,cheerfulstoic/brakeman,lee-leon/brakeman,kbrock/brakeman,bf4/brakeman,spcoder/brakeman,liqites/brakeman,htdc/brakeman,oreoshake/brakeman,dfens/brakeman,bf4/brakeman,lee-leon/brakeman,masarakki/brakeman,jakeatwork/brakeman