Add :api_keys option for API keys file
Merge pull request #1 from takei-yuya/feature/load_api_keys_from_file

Add :api_keys option for API keys file
Changed reference URL of source in Gemfile.
Merge pull request #2 from ofk/feature/change-source-in-gemfile

Changed reference URL of source in Gemfile.
Release v1.0.1
Merge branch 'release/1.0.1' into develop