Add python syntax designation to code example

Author: DavidMuller

README.md

@@ -10,7 +10,7 @@
 
 # Example Usage
 
-```
+```python
 from guidebook import api_requestor
 
 api_key = 'example_key'
@@ -20,7 +20,6 @@ api_client = api_requestor.APIRequestor(api_key)
 api_url = 'https://builder.guidebook.com/open-api/v1/sessions/'
 
 api_client.request('get', api_url)
-
 ```