improvement: style tweaks

lib/widgets/mutation_button.dart

@@ -0,0 +1,32 @@
+import 'package:flutter/cupertino.dart';
+import 'package:git_touch/models/theme.dart';
+import 'package:provider/provider.dart';
+
+class MutationButton extends StatelessWidget {
+  final String text;
+  final VoidCallback onPressed;
+
+  MutationButton({
+    @required this.text,
+    @required this.onPressed,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Provider.of<ThemeModel>(context);
+    return CupertinoButton(
+      onPressed: onPressed,
+      minSize: 0,
+      color: theme.palette.primary,
+      padding: EdgeInsets.symmetric(
+        horizontal: 12,
+        vertical: 4,
+      ),
+      borderRadius: BorderRadius.all(Radius.circular(20)),
+      child: Text(
+        text,
+        style: TextStyle(fontSize: 16, color: theme.palette.background),
+      ),
+    );
+  }
+}