add github-username
Merge pull request #2 from tacahilo/fix-readme

add github-username
undefined constant Logger
Merge pull request #3 from cho45/require

undefined constant Logger with only require 'log_minimal'
Output log to $stderr by default.
Fixed test
Merge pull request #4 from cho45/default-stderr

Output log to $stderr by default.
change default log level

from $stderr to $stdout
Merge pull request #5 from ryopeko/change_default_log_level

change default log level
added build-status