Improve README.md
Improve README.md

yui-knk/byebug,guilherme/byebug,deivid-rodriguez/byebug,edward/byebug,icebreaker/byebug,k0kubun/byebug,ozydingo/byebug,davidmowrer/in_class_projects_t2,k0kubun/byebug,miamiruby/byebug,deivid-rodriguez/byebug,deivid-rodriguez/byebug,saisai/byebug,phusion/byebug,yui-knk/byebug,guilherme/byebug,os97673/byebug,guilherme/byebug,phusion/byebug,scalp42/byebug,k0kubun/byebug,webdev1001/byebug,scalp42/byebug,davidmowrer/in_class_projects_t2,miamiruby/byebug,ozydingo/byebug,os97673/byebug,webdev1001/byebug,saisai/byebug,davidmowrer/in_class_projects_t2,icebreaker/byebug,yui-knk/byebug,edward/byebug