add coveralls gem
add coveralls setting
update Gemfile.lock for updating Gemfile
Add badges
Add better_errors gem
move spring gem into group :development block
add pry gems
modify Gemfile
add pry-byebug, binding-of-caller
resolbe confilct, close #177
Merge pull request #178 from i-d-e-a-t/make-more-comfortable

便利なツールやGemを導入