Add documentation to Fix permission for make file #88 (#89)

Author: fragm3

README.md

@@ -72,11 +72,11 @@ To set up the development environment, install the packages mentioned in depende
 
 First install sphinx by running following command
 
-    pip install -U Sphinx
+    sudo pip install -U Sphinx
 
 Then go to pslab/docs and run the following command
 
-    $ make html
+    $ sudo make html
 
 ### Blog posts related to PSLab on FOSSASIA blog 
 * [Installation of PSLab](http://blog.fossasia.org/pslab-code-repository-and-installation/)