Add clone() method to Field to get clean copies of it.

django/db/models/fields/__init__.py

@@ -240,6 +240,14 @@ class Field(object):
             keywords,
         )
 
+    def clone(self):
+        """
+        Uses deconstruct() to clone a new copy of this Field.
+        Will not preserve any class attachments/attribute names.
+        """
+        name, path, args, kwargs = self.deconstruct()
+        return self.__class__(*args, **kwargs)
+
     def __eq__(self, other):
         # Needed for @total_ordering
         if isinstance(other, Field):