Fix the CircleCI badge in the README.
Fix the CircleCI badge in the README.

joshua5201/administrate,vgsantoniazzi/administrate,vgsantoniazzi/administrate,thoughtbot/administrate,BenMorganIO/administrate,dminchev/administrate,BenMorganIO/administrate,nando/administrate,joshua5201/administrate,thoughtbot/administrate,dminchev/administrate,nando/administrate,dminchev/administrate,vgsantoniazzi/administrate,joshua5201/administrate,nando/administrate,joshua5201/administrate,dminchev/administrate,thoughtbot/administrate,nando/administrate,thoughtbot/administrate,vgsantoniazzi/administrate,BenMorganIO/administrate,BenMorganIO/administrate