Adding all tracks, I guess

dart/hello-world/README.md

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+# Hello World
+
+The classical introductory exercise. Just say "Hello, World!".
+
+["Hello, World!"](http://en.wikipedia.org/wiki/%22Hello,_world!%22_program) is
+the traditional first program for beginning programming in a new language
+or environment.
+
+The objectives are simple:
+
+- Write a function that returns the string "Hello, World!".
+- Run the test suite and make sure that it succeeds.
+- Submit your solution and check it at the website.
+
+If everything goes well, you will be ready to fetch your first real exercise.
+
+
+To run the tests:
+
+```sh
+$ pub run test
+```
+
+For more detailed info about the Dart track see the [help page](http://exercism.io/languages/dart).
+
+## Source
+
+This is an exercise to introduce users to using Exercism [http://en.wikipedia.org/wiki/%22Hello,_world!%22_program](http://en.wikipedia.org/wiki/%22Hello,_world!%22_program)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.

dart/hello-world/lib/hello_world.dart

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+class HelloWorld {
+  String hello() {
+    // Put your code here
+  }
+}

dart/hello-world/pubspec.yaml

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+name: 'hello_world'
+dev_dependencies:
+  test: '<0.13.0'

dart/hello-world/test/hello_world_test.dart

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+import 'package:test/test.dart';
+import 'package:hello_world/hello_world.dart';
+
+void main() {
+  test("Say Hi!", () {
+    expect(new HelloWorld().hello(), equals("Hello, World!"));
+  });
+}