do not use python user site

singularity/Singularity.1.0

@@ -22,6 +22,7 @@ from: ubuntu:bionic
     #################################
     #        installing craw        #
     #################################
+    export PYTHONNOUSERSITE=1
 	pip3 install craw==1.0
 
     #################################
@@ -34,6 +35,12 @@ from: ubuntu:bionic
 %test
     /usr/bin/python3 /craw/tests/run_tests.py -vv
 
+%environment
+    # to be reproducible we should nevr search
+    # in python user cache which is the user home
+    # and is mounted automically
+    export PYTHONNOUSERSITE=1
+
 %help
     This singularity image contains the Counter RNAseq Window (CRAW) package.
     Two commands are available \"coverage\" and \"htmp\.