add type to cell interface

bolt/internal/internal_test.go

@@ -84,6 +84,7 @@ func TestMarshalLayout(t *testing.T) {
 				W:    4,
 				H:    4,
 				I:    "anotherid",
+				Type: "line",
 				Name: "cell1",
 				Queries: []chronograf.Query{
 					{

chronograf.go

@@ -260,6 +260,7 @@ type Cell struct {
 	I       string  `json:"i"`
 	Name    string  `json:"name"`
 	Queries []Query `json:"queries"`
+	Type    string	`json:"type"`
 }
 
 // Layout is a collection of Cells for visualization