Updated README missed in release.
Updated README missed in release.

dblock/slack-bot-server,dblock/slack-ruby-bot-server,dblock/slack-bot-server,slack-ruby/slack-ruby-bot-server,dblock/slack-ruby-bot-server,slack-ruby/slack-ruby-bot-server,dblock/slack-ruby-bot-server,slack-ruby/slack-ruby-bot-server,dblock/slack-bot-server,dblock/slack-bot-server