def get_vrule(service_name = nil, section_name = nil, graph_name = nil)
      path = "/vrule/summary"
      path += "/#{e service_name}" if service_name
      path += "/#{e section_name}" if section_name
      path += "/#{e graph_name}"   if graph_name
      get_json(path)
    end
def get_vrule(service_name = nil, section_name = nil, graph_name = nil)
      path = "/vrule/summary"
      path += "/#{e service_name}" if service_name
      path += "/#{e section_name}" if section_name
      path += "/#{e graph_name}"   if graph_name
      get_json(path)
    end
Get the data of vrules, GET /vrule/summary/:service_name/:section_name/:graph_name
 @param [String] service_name
 @param [String] section_name
 @param [String] graph_name
 @return [Hash] the data of vrules
 @example
[
{
  "graph_path"=>"/hoge/hoge/hoge",
  "color"=>"#FF0000",
  "time"=>1395826210,
  "id"=>1,
  "dashes"=>"",
  "description"=>""
},
{
  "graph_path"=>"/hoge/hoge/hoge",
  "color"=>"#FF0000",
  "time"=>1395826363,
  "id"=>2,
  "dashes"=>"2,10",
  "description"=>""
}
]