small changes, updated readme

using_gradient/lib/main.dart

@@ -20,6 +20,7 @@ void main() {
                 // Add Text
                 child: new Text(
                   "Hello World!",
+                  style: new TextStyle(color: Colors.white),
                 ),
               ),
               // Set background

using_gradient/lib/utils.dart

@@ -3,7 +3,7 @@ import 'package:flutter/material.dart';
 LinearGradient getCustomGradient() {
   // Define a Linear Gradient
   return new LinearGradient(
-      colors: [Colors.lightBlueAccent, Colors.blueAccent],
+      colors: [Colors.pink, Colors.blueAccent],
       begin: const FractionalOffset(0.0, 0.0),
       end: const FractionalOffset(0.6, 0.0),
       stops: [0.0, 0.6],