Added long_description and classifiers to the setup

setup.py

@@ -29,6 +29,8 @@ setup(name="pygeodyn",
       author=authors,
       author_email='loic.huder@univ-grenoble-alpes.fr',
       description='Python package for geomagnetic data assimilation',
+      long_description=open('README.md').read(),
+      long_description_content_type='text/markdown',
       url='https://gricad-gitlab.univ-grenoble-alpes.fr/Geodynamo/pygeodyn',
       packages=setuptools.find_packages(),
       ext_modules=[Extension(name="fortran",
@@ -37,8 +39,11 @@ setup(name="pygeodyn",
       install_requires=['h5py', 'numpy>=1.10', 'scipy>=0.17', 'matplotlib', 'mpi4py', 'sklearn'],
       tests_require=['hypothesis'],
       classifiers=[
+          'Programming Language :: Python :: 3 :: Only'
           'Programming Language :: Python :: 3.5',
+          'Programming Language :: Python :: 3.6',
           'License :: OSI Approved :: GNU General Public License v3 (GPLv3)',
-          'Intended Audience :: Science/Research'
+          'Intended Audience :: Science/Research',
+          'Topic :: Scientific/Engineering :: Physics'
       ]
       )