Add part9

intro/part9/README.md

@@ -0,0 +1,17 @@
+# Part 8
+
+Once again, we'll be building `src/Main.elm`, but editing a different file.
+
+To build everything, `cd` into the `part8/` directory and run8
+
+```shell
+elm make src/Main.elm --output ../server/public/elm.js
+```
+
+Then open `http://localhost:3000` in your browser.
+
+## Exercise
+
+We need to make login work. Currently it doesn't actually send a HTTP request to the server.
+
+We'll fix this by editing `src/Page/Login.elm` and resolving the TODOs there.