added scheme test

homework/tbdTest.rkt

@@ -0,0 +1,13 @@
+#lang racket
+
+(require rackunit "tbd.rkt")
+
+(define hw-tests
+  (test-suite "scheme unit tests"
+              
+   (test-case "test fail"
+    (begin
+      (check-equal? 3 4)))))
+
+(require rackunit/gui)
+(test/gui hw-tests)

lectures/index.md

@@ -2,3 +2,4 @@
 * [semiotics](./semiotics.md)
 * [languages and machines](./chomsky.md)
 * [all about names](./names.md)
+* [lambda calculus](./lambda.md)