Added covid-19 example app and Updated the readme (#73)

covid19_mobile_app/lib/widgets/info_card.dart

@@ -0,0 +1,31 @@
+import 'package:flutter/material.dart';
+
+// this is the rounded rectangle card widget that appears on the homescreen
+Widget infoCard(BuildContext context, String title, String number) {
+  return Card(
+    child: Column(
+      mainAxisAlignment: MainAxisAlignment.center,
+      children: <Widget>[
+        Text(
+          title,
+          textAlign: TextAlign.center,
+          style: TextStyle(
+            fontSize: MediaQuery.of(context).size.height * 0.03,
+          ),
+        ),
+        SizedBox(
+          height: 5.0,
+        ),
+        Text(
+          number,
+          textAlign: TextAlign.center,
+          style: TextStyle(
+            fontSize: 20.0,
+          ),
+        ),
+      ],
+    ),
+    shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(40.0)),
+    color: Color(0xfff44e3f),
+  );
+}