initial
init rspec
simple merge
pass options for document keys
refactor merger
add test case
extract Group inner class
add complex merge pattern
manage by Gemfile
simple merge with Hashie
change merge strategy
more test case
add test case
rename to Tsugo
modify interface for merge by key
modify interface for merge by key
Merge branch 'master' of https://github.com/haazime/tsugo