updated README; added Travis badge

Author: sommersoft

README.rst

@@ -10,6 +10,10 @@ Introduction
     :target: https://discord.gg/nBQh6qu
     :alt: Discord
 
+.. image:: https://travis-ci.org/adafruit/Adafruit_CircuitPython_LIS3DH.svg?branch=master
+    :target: https://travis-ci.org/adafruit/Adafruit_CircuitPython_LIS3DH
+    :alt: Build Status
+
 Adafruit CircuitPython module for the LIS3DH accelerometer.
 
 Note this module is made to work with CircuitPython and not MicroPython APIs.