diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..a630ed4
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+*.swp
+go.mod
+go.sum
diff --git a/README b/README.md
similarity index 92%
rename from README
rename to README.md
index 52dc2e4..7d03c37 100644
--- a/README
+++ b/README.md
@@ -41,3 +41,6 @@ the compiler itself should use. I would suggest making
 
 This package would be better as golang.org/iter but I don't
 know who to ask about doing that.
+
+coro.go patch:
+~/go/src/go.googlesource.com/go/src/iter$ git whatchanged -1 -p a9c9cc07ac0d3dc73865a57e6ce45c22ada3b5c9