add url and download url

setup.py

@@ -14,6 +14,8 @@ metainfo = {
         },
     'version': version,
     'license': 'GPLv3',
+    'download_url': ['https://pypi.org/project/rpg/'],
+    'url': ['https://pypi.org/project/rpg/'],
     'description': 'In silico protein digestion',
     'platforms': ['Linux', 'Unix', 'MacOsX', 'Windows'],
     "keywords": ["protein", "peptide", "enzyme", "protease", "digestion"],
@@ -55,6 +57,8 @@ setup(
     description=metainfo['description'],
     license=metainfo['license'],
     platforms=metainfo['platforms'],
+    url=metainfo['url'],
+    download_url=metainfo['download_url'],
     classifiers=metainfo['classifiers'],
     zip_safe=False,
     packages=find_packages(),