Fixed RegattaDataSource missing.

-RegattaDataSource failed to push from before. It is now created and working.

#story[778]

mock/src/main/java/seng302/Mock/RegattaDataSource.java

@@ -0,0 +1,8 @@
+package seng302.Mock;
+
+/**
+ * Created by zwu18 on 25/04/17.
+ */
+public interface RegattaDataSource{
+    Regatta getRegatta();
+}