Add package level documentation and citation information

Change-Id: I109311d37747d7c65bd7db893f10e25ebe432e3a
diff --git a/DESCRIPTION b/DESCRIPTION
index 418805e..0b416f1 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -26,5 +26,6 @@
 Collate: 
     'utils-pipe.R'
     'derekovecs.R'
+    'rderekovecs-package.R'
 Roxygen: list(markdown = TRUE)
 Config/testthat/edition: 3