diff --git a/.dockerignore b/.dockerignore
new file mode 100644
index 0000000..2fd6b6d
--- /dev/null
+++ b/.dockerignore
@@ -0,0 +1,8 @@
+img
+
+Dockerfile
+.git*
+part*.html
+CONTRIBUTING.md
+LICENSE
+README.md
\ No newline at end of file
diff --git a/Dockerfile b/Dockerfile
index ebc8935..9b2d6c5 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -9,4 +9,4 @@ RUN stack build
 COPY exercises /usr/src/app
 
 # modify next line to change the wanted exercise
-CMD ["stack", "runhaskell", "Set3aTest.hs"]
\ No newline at end of file
+CMD ["stack", "runhaskell", "Set3bTest.hs"]
\ No newline at end of file