add migrate.__version__ (Fixes issue 111)

- add __version__ to migrate/__init__.py
- add test in migrate/tests/__init__.py
- update docs/changelog.rst

docs/changelog.rst

@@ -5,6 +5,7 @@ Features
 ******************
 
 - compatibility with SQLAlchemy 0.7
+- add migrate.__version__
 
 Fixed bugs
 ******************

migrate/__init__.py

@@ -7,3 +7,5 @@
 
 from migrate.versioning import *
 from migrate.changeset import *
+
+__version__ = '0.7'

migrate/tests/__init__.py

@@ -2,3 +2,14 @@
 import sys
 import os
 sys.path.append(os.path.dirname(os.path.abspath(__file__)))
+
+
+from unittest import TestCase
+import migrate
+
+
+class TestVersionDefined(TestCase):
+    def test_version(self):
+        """Test for migrate.__version__"""
+        self.assertTrue(isinstance(migrate.__version__, basestring))
+        self.assertTrue(len(migrate.__version__) > 0)