Relicense this repository under the Apache v2 and MIT licenses.

* Move licensing information to the top level of the repo.
* Add README.md file with license and contributing info.

LICENSE.txt → LICENSE

@@ -3,7 +3,8 @@ and MIT licenses. The user can choose the license under which they
 will be using the software. There may be other licenses within the
 distribution with which the user must also comply.
 
-See the files LICENSE-APACHE.txt and LICENSE-MIT.txt for the full text
-of the licenses.
-
-
+See the files
+  https://github.com/racket/racket/blob/master/racket/src/LICENSE-APACHE.txt
+and
+  https://github.com/racket/racket/blob/master/racket/src/LICENSE-MIT.txt
+for the full text of the licenses.

README.md

@@ -0,0 +1,24 @@
+# class-iop
+
+This the source for the Racket packages: "class-iop", "class-iop-doc", "class-iop-lib".
+
+### Contributing
+
+Contribute to Racket by submitting a [pull request], reporting an
+[issue], joining the [development mailing list], or visiting the
+IRC or Slack channels.
+
+### License
+
+Racket, including these packages, is free software, see [LICENSE]
+for more details.
+
+By making a contribution, you are agreeing that your contribution
+is licensed under the [Apache 2.0] license and the [MIT] license.
+
+[MIT]: https://github.com/racket/racket/blob/master/racket/src/LICENSE-MIT.txt
+[Apache 2.0]: https://www.apache.org/licenses/LICENSE-2.0.txt
+[pull request]: https://github.com/racket/class-iop/pulls
+[issue]: https://github.com/racket/class-iop/issues
+[development mailing list]: https://lists.racket-lang.org
+[LICENSE]: LICENSE