Mention ActiveRecord specific hooks in the README.markdown
Mention ActiveRecord specific hooks in the README.markdown

Mention that for ActiveRecord one should be using after_commit and after_rollback.

Closes #603.

ChapterMedia/tire,iamrahulroy/retire,fabn/retire,dbose/retire,HenleyChiu/tire,elbuo8/retire,mavenlink/retire,Telmate/tire,rubydubee/retire,tklee/tire_shiphawk,brijeshgpt7/retire,doximity/tire,karmi/retire,zaharpecherin/retire,1776/tire