Add reference files to Gentrap summary

public/gentrap/src/main/scala/nl/lumc/sasc/biopet/pipelines/gentrap/Gentrap.scala

@@ -268,6 +268,10 @@ class Gentrap(val root: Configurable) extends QScript with MultiSampleQScript wi
 
   /** Files that will be listed in the summary file */
   def summaryFiles: Map[String, File] = Map(
+    // NOTE: technically we can use different references in each of the sample, but for simplicity's sake we store the
+    //       reference information in the pipeline level now.
+    "reference_fasta" -> reference,
+    "reference_dict" -> referenceDict,
     "annotation_refflat" -> annotationRefFlat
   ) ++ Map(
       "annotation_gtf" -> annotationGtf,