Rollbar logger

[jondeandres]

This PR provides the class Rollbar::Logger that inherits from Logger and can be used to log the application messages to Rollbar using a logger interface.

Usage:

require 'rollbar/logger'

logger = Rollbar::Logger.new

logger.info('Something happened!')

This looks like using just Rollbar.info for the same, but, if using Rails, you can extend Rails.logger so all the Rails log is sent to Rollbar. By default messages with severity >= ERROR. Usage in a Rails initializer:

require 'rollbar/logger'

Rails.logger.extend(ActiveSupport::Logger.broadcast(Rollbar::Logger.new))