Freeze ./integration and explain where to contribute new tests

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)

integration/MAINTAINERS

@@ -0,0 +1,4 @@
+Solomon Hykes <s@docker.com>
+# WE ARE LOOKING FOR VOLUNTEERS TO HELP CLEAN THIS UP.
+# TO VOLUNTEER PLEASE OPEN A PULL REQUEST ADDING YOURSELF TO THIS FILE.
+# WE WILL HELP YOU GET STARTED. THANKS!

integration/README.md

@@ -0,0 +1,23 @@
+## Legacy integration tests
+
+`./integration` contains Docker's legacy integration tests.
+It is DEPRECATED and will eventually be removed.
+
+### If you are a *CONTRIBUTOR* and want to add a test:
+
+* Consider mocking out side effects and contributing a *unit test* in the subsystem
+you're modifying. For example, the remote API has unit tests in `./api/server/server_unit_tests.go`.
+The events subsystem has unit tests in `./events/events_test.go`. And so on.
+
+* For end-to-end integration tests, please contribute to `./integration-cli`.
+
+
+### If you are a *MAINTAINER*
+
+Please don't allow patches adding new tests to `./integration`.
+
+### If you are *LOOKING FOR A WAY TO HELP*
+
+Please consider porting tests away from `./integration` and into either unit tests or CLI tests.
+
+Any help will be greatly appreciated!