Implemented referencing cached collection.

Change-Id: I02f2ee84b3f8e50c5632efc9363eb87d97a754f8
diff --git a/.gitignore b/.gitignore
index 04618c9..a89d9ae 100644
--- a/.gitignore
+++ b/.gitignore
@@ -24,4 +24,5 @@
 /src/main/resources/korap.conf
 /dependency-reduced-pom.xml
 /bin
-/src/test/resources/sample-index
\ No newline at end of file
+/src/test/resources/sample-index
+/krill_cache/