Created the populatedDrawer widget and the Avatar widget

lib/src/widgets/avatar.dart

@@ -0,0 +1,39 @@
+import 'package:flutter/material.dart';
+import 'package:font_awesome_flutter/font_awesome_flutter.dart';
+
+class Avatar extends StatelessWidget {
+  /// The url of hte image to be displayed.
+  final String imageUrl;
+
+  /// The size of the Avatar.
+  final double size;
+
+  Avatar({
+    this.imageUrl,
+    this.size = 60.0,
+  });
+
+  Widget build(BuildContext context) {
+    return imageUrl == null
+        ? Container(
+            height: size,
+            width: size,
+            decoration: BoxDecoration(
+              color: Colors.white,
+              borderRadius: BorderRadius.circular(30),
+            ),
+            child: Center(
+              child: Icon(
+                FontAwesomeIcons.question,
+              ),
+            ),
+          )
+        : ClipOval(
+            child: Image.network(
+              imageUrl,
+              height: size,
+              width: size,
+            ),
+          );
+  }
+}