explicitly include CHANGELOG, LICENSE and README.rst in package

Author: joernhees

MANIFEST.in

@@ -0,0 +1,3 @@
+include README.rst
+include CHANGELOG
+include LICENSE

setup.py

@@ -46,6 +46,7 @@
     ],
     keywords='docker user limit admin hpc cluster computing permissions',
     packages=find_packages(),
+    include_package_data=True,
     data_files=[('/etc/userdocker/', ['userdocker/config/default.py'])],
     entry_points={'console_scripts': ['userdocker=userdocker.userdocker:main']},
     zip_safe=True,