added instructions to update BLISS.

README.md

@@ -6,4 +6,18 @@ Bliss
 
 The bliss control library.
 
-Latest documentation from master can be found [here](http://bliss.gitlab-pages.esrf.fr/bliss/master)
\ No newline at end of file
+Latest documentation from master can be found [here](http://bliss.gitlab-pages.esrf.fr/bliss/master)
+
+
+In short
+========
+
+To update BLISS from source:
+```
+conda install --file ./requirements-conda.txt
+pip install --no-deps -e .
+```
+
+
+
+