Include migration mako script (#123)

Fixes  #122

Author: shosca

MANIFEST.in

@@ -1,4 +1,5 @@
 include *.rst *.txt
 recursive-include tests *
+recursive-include django_sorcery *.mako *.py
 recursive-exclude * __pycache__
 recursive-exclude * *.py[co]

setup.py

@@ -37,6 +37,7 @@ def read(fname):
     author=about["__author__"],
     author_email=about["__author_email__"],
     description=about["__description__"],
+    include_package_data=True,
     install_requires=["alembic", "blinker", "six", 'Django<2;python_version<"3"', "Django", "SQLAlchemy"],
     license="MIT",
     long_description=read("README.rst"),