Add bug report page.

docs/bugs.md

@@ -0,0 +1,46 @@
+# Filing bugs
+
+[target package]: https://github.com/kubernetes-sigs/kustomize/tree/master/pkg/target
+[example of a target test]: https://github.com/kubernetes-sigs/kustomize/blob/master/pkg/target/baseandoverlaysmall_test.go
+
+File issues as desired, but
+if you've found a problem with how
+`kustomize build` works, consider the
+following to improve response time.
+
+## A good report specifies
+
+ * the output of `kustomize version`,
+ * the input (the content of `kustomization.yaml`
+   and any files it refers to),
+ * the expected YAML output.
+
+## A great report is a bug reproduction test
+
+kustomize has a simple test harness in the
+[target package] for specifying a kustomization's
+input and the expected output.
+See this [example of a target test].
+
+The pattern is
+ * call `NewKustTestHarness`
+ * specify kustomization input data (resources,
+   patches, etc.) as inline strings,
+ * call `makeKustTarget().MakeCustomizedResMap()`
+ * compare the actual output to expected output
+
+In a bug reproduction test, the expected output
+string initially contains the _wrong_ (unexpected)
+output, thus unambiguously reproducing the bug.
+
+Nearby comments should explain what the output
+should be, and have a TODO pointing to the related
+issue.
+
+The person who fixes the bug then has a clear bug
+reproduction and a test to modify when the bug is
+fixed.
+
+The bug reporter can then see the bug was fixed,
+and has permanent regression coverage to prevent
+its reintroduction.