class PingController  < ApplicationController
  respond_to :json

  def index
    to_ret = { :version_number => VERSION_INFO['version_number'], :build_date => VERSION_INFO['build_date'],
      :commit_id => VERSION_INFO['commit'], :build_tag => VERSION_INFO['build_tag'] }
    respond_with to_ret.to_json
  end
end
class PingController  < ApplicationController
  def index
    render json: {
      :version_number => VERSION_INFO['version_number'],
      :build_date => VERSION_INFO['build_date'],
      :commit_id => VERSION_INFO['commit'],
      :build_tag => VERSION_INFO['build_tag']
    }
  end
end

Stop using respond_to feature removed from Rails
Stop using respond_to feature removed from Rails

It's not useful in any case, as the same can be achieved by rendering
JSON explicitly.
