Add dotenv configuration provider

test/config_test.dart

@@ -10,4 +10,5 @@ void main() {
     expect(value, equals(result));
     expect(value, equals(SystemConfig.getOrNull(key)));
   });
+  
 }

test/dotenv_test.dart

@@ -0,0 +1,20 @@
+import 'package:configurable/dotenv/dotenv.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test('just call env', () {
+    load();
+  
+    var result = env['app.name'];
+
+    expect('CUBETIQ Solution', equals(result));
+  });
+
+  test('get export variable', () {
+    load();
+
+    var result = env['NAME'];
+
+    expect('Sambo Chea', equals(result));
+  });
+}