Restructure & update setup file

setup.py

@@ -1,36 +1,42 @@
 import setuptools
 
-with open("README.rst", "r", encoding="utf8") as f:
-    long_description = f.read()
+with open("docs/index.md", "r", encoding="utf8") as f:
+    LONG_DESCRIPTION = f.read()
+
+PROJECT_URLS = {"Documentation": "https://appelpy.readthedocs.io/",
+                "Source": "https://github.com/mfarragher/appelpy"}
+INSTALL_REQUIRES = ["pandas>=0.24", "jinja2",
+                    "scipy",
+                    "numpy>=1.16",
+                    "statsmodels>=0.9", "patsy",
+                    "seaborn>=0.9",
+                    "matplotlib>=3"]
+CLASSIFIERS = [
+    "Development Status :: 3 - Alpha",
+    "Intended Audience :: Education",
+    "Intended Audience :: Science/Research",
+    "Topic :: Scientific/Engineering :: Mathematics",
+    "Topic :: Office/Business :: Financial",
+    "Programming Language :: Python :: 3.6",
+    "Programming Language :: Python :: 3.7",
+    "License :: OSI Approved :: BSD License",
+    "Operating System :: OS Independent",
+]
 
 setuptools.setup(
     name="appelpy",
-    version="0.4.0",
+    version="0.4.1",
     author="Mark Farragher",
     description="Applied Econometrics Library for Python",
-    long_description=long_description,
+    long_description=LONG_DESCRIPTION,
     long_description_content_type="text/markdown",
     keywords=["econometrics", "regression",
               "statistics", "economics", "models"],
     url="https://github.com/mfarragher/appelpy",
+    project_urls=PROJECT_URLS,
     packages=setuptools.find_packages(),
-    python_requires=">=3",
-    install_requires=["pandas>=0.24", "jinja2",
-                      "scipy",
-                      "numpy>=1.16",
-                      "statsmodels>=0.9", "patsy",
-                      "seaborn>=0.9",
-                      "matplotlib>=3"],
+    python_requires=">=3.6",
+    install_requires=INSTALL_REQUIRES,
     license="BSD",
-    classifiers=[
-        "Development Status :: 3 - Alpha",
-        "Intended Audience :: Education",
-        "Intended Audience :: Science/Research",
-        "Topic :: Scientific/Engineering :: Mathematics",
-        "Topic :: Office/Business :: Financial",
-        "Programming Language :: Python :: 3.6",
-        "Programming Language :: Python :: 3.7",
-        "License :: OSI Approved :: BSD License",
-        "Operating System :: OS Independent",
-    ],
+    classifiers=CLASSIFIERS
 )