Update README.md for first time users

Author: nthapaliya

README.md

@@ -1,2 +1,15 @@
 # api_client_python
 Some examples to show how to interact with the OfficeSpace API using Python
+
+# Prerequisites
+
+## External libraries
+This script depends on the python library `requests` to work. Make sure
+it is installed before running.
+
+A quick way install `requests` if it isn't yet:
+```bash
+sudo easy_install pip
+sudo pip install --upgrade pip
+pip install requests
+```