Update README

README.md

@@ -1,5 +1,33 @@
-extras-mongoengine
+MongoEngine Extras
 ==================
 
-MongoEngine Extras - Field Types and any other wizardry.
+The `extras-mongoengine` package provides the following extra fields for use on
+MongoEngine `Document`s:
 
+* `TimedeltaField` - a field for storing `datetime.timedelta` values.
+* `LowerStringField` - a string field that transforms input strings to lowercase.
+* `LowerEmailField` – a `LowerStringField` that also check if the string is valid according
+   to the MongoEngine email regex (`EmailField.EMAIL_REGEX`).
+* `IntEnumField` - a field for storing Python 3.4 (or later) [Enum values] where the values
+  in the enum are `int`s.
+* `StringEnumField` - a field for storing Python 3.4 (or later) [Enum values] where the values
+  in the enum are `str`s.
+
+[Enum values]: https://docs.python.org/3/library/enum.html
+
+To use the `IntEnumField` and `StringEnumField` fields on Python 2.* or Python <3.4
+you have to install the `enum34` package.
+
+`StringEnumField` example
+-------------------------
+
+	from mongoengine import Document
+	from enum import Enum
+	from extras_mongoengine.fields import StringEnumField
+
+	class BeverageType(Enum):
+	    Tea = 'TEA'
+	    Coffee = 'COFFEE'
+
+	class Beverage(Document):
+	    beverage_type = StringEnumField(BeverageType, default=BeverageType.Tea)