Added some more docstrings to entities.

platypush/entities/devices.py

@@ -8,6 +8,10 @@ from ._base import Entity
 if 'device' not in Base.metadata:
 
     class Device(Entity):
+        """
+        Base class to model device entities.
+        """
+
         __tablename__ = 'device'
 
         id = Column(

platypush/entities/dimmers.py

@@ -8,6 +8,11 @@ from .devices import Device
 if 'dimmer' not in Base.metadata:
 
     class Dimmer(Device):
+        """
+        This class models dimmer entities. A dimmer is any actionable entity
+        with numeric values and an optional min/max range.
+        """
+
         __tablename__ = 'dimmer'
 
         id = Column(