diff --git a/src/main/java/pythagoras/Pythagoras.gwt.xml b/src/main/java/pythagoras/Pythagoras.gwt.xml
new file mode 100644
index 0000000..9ce0b8a
--- /dev/null
+++ b/src/main/java/pythagoras/Pythagoras.gwt.xml
@@ -0,0 +1,6 @@
+<!-- defines our GWT module -->
+<module>
+  <source path="f"/>
+  <source path="d"/>
+  <source path="i"/>
+</module>