Bar graph added.

node_modules/canvas/src/Backends.cc

@@ -0,0 +1,18 @@
+#include "Backends.h"
+
+#include "backend/ImageBackend.h"
+#include "backend/PdfBackend.h"
+#include "backend/SvgBackend.h"
+
+using namespace v8;
+
+void Backends::Initialize(Local<Object> target) {
+  Nan::HandleScope scope;
+
+  Local<Object> obj = Nan::New<Object>();
+  ImageBackend::Initialize(obj);
+  PdfBackend::Initialize(obj);
+  SvgBackend::Initialize(obj);
+
+  Nan::Set(target, Nan::New<String>("Backends").ToLocalChecked(), obj).Check();
+}