Add .gitignore; ignore Gemfile.lock
Add .gitignore; ignore Gemfile.lock

mururu/fluent-plugin-google-cloud,senthilkumar-kj/fluent-plugin-google-cloud,brint/fluent-plugin-google-cloud,swalkowski/fluent-plugin-google-cloud,hakobera/fluent-plugin-google-cloud,cosmo0920/fluent-plugin-google-cloud,laramiel/fluent-plugin-google-cloud,arthurdarcet/fluent-plugin-google-cloud,GoogleCloudPlatform/fluent-plugin-google-cloud,a-robinson/fluent-plugin-google-cloud