started learning 372 bullet
fixed the ruby and gemset version
update the current version to 3.2.15
added bullet and n plus one detected
included to solve the n + 1 problem
unnecessary enhancement detected
removed and start counter cache
added counter cache
migration for the counter filed
Finished 372 bullet about n plus 1 and counter cache
Merge pull request #268 from fireweb/master

Finished 372 bullet about n +1 and cache counter