Merge pull request #1 from adafruit/lib_files

adding library, docs, example

README.rst

@@ -92,8 +92,23 @@ Usage Example
 =============
 
 .. code-block:: python
+
+    import time
+    import board
     import adafruit_ina228
 
+    i2c = board.I2C()
+    ina228 = adafruit_ina228.INA228(i2c)
+
+    while True:
+        print(f"Current: {ina228.current:.2f} mA")
+        print(f"Bus Voltage: {ina228.voltage:.2f} V")
+        print(f"Shunt Voltage: {ina228.shunt_voltage*1000:.2f} mV")
+        print(f"Power: {ina228.power:.2f} mW")
+        print(f"Energy: {ina228.energy:.2f} J")
+        print(f"Temperature: {ina228.temperature:.2f} °C")
+        time.sleep(1)
+
 Documentation
 =============
 API documentation for this library can be found on `Read the Docs <https://docs.circuitpython.org/projects/ina228/en/latest/>`_.