Add the gitlab url in the setup.py

setup.py

@@ -13,7 +13,7 @@ setuptools.setup(
     description="A set of ipywidgets UI for jupyter notebook",
     long_description=long_description,
     long_description_content_type="text/markdown",
-    url="",
+    url="https://gitlab.com/discosoleil/nbui",
     packages=setuptools.find_packages(),
     classifiers=[
         "Programming Language :: Python :: 3",