Update README.rst, adding pandas example

Author: jovezhong

README.rst

@@ -89,3 +89,42 @@ Insert Data
 
   # create a random stream if not exist
   c.execute("INSERT INTO proton_stream (raw) VALUES",rows) #rows is an array of arrays
+
+Pandas DataFrame
+----------------
+Big fan of Pandas? We too! You can mix SQL and Pandas API together:
+
+.. code-block:: python
+
+   import pandas as pd
+   import time
+   
+   from proton_driver import client
+   
+   if __name__ == "__main__":
+       c = client.Client(host='127.0.0.1', port=8463)
+   
+       # setup the test stream
+       c.execute("drop stream if exists test")
+       c.execute("""create stream test (
+                       year int16,
+                       first_name string
+                   )""")
+       # add some data
+       df = pd.DataFrame.from_records([
+           {'year': 1994, 'first_name': 'Vova'},
+           {'year': 1995, 'first_name': 'Anja'},
+           {'year': 1996, 'first_name': 'Vasja'},
+           {'year': 1997, 'first_name': 'Petja'},
+       ])
+       c.insert_dataframe(
+           'INSERT INTO "test" (year, first_name) VALUES',
+           df,
+           settings=dict(use_numpy=True),
+       )
+       # or c.execute("INSERT INTO test(year, first_name) VALUES", df.to_dict('records'))
+       time.sleep(3) # wait for 3 sec to make sure data available in historical store
+   
+       df = c.query_dataframe('SELECT * FROM table(test)')
+       print(df)
+       print(df.describe())