added Gemfile.lock.
run "rails new .".
added twitter to Gemfile.
run "bundle exec rails generate controller Tweets".
added puma to Gemfile.
added underscore-rails to Gemfile.
added rails_config to Gemfile.
run "bundle exec rails generate rails_config:install".
added underscore to application.js.
change underscore.js settings.
Show twitter's tweets.