add dependency to setup.py

Author: Jencir Lee

setup.py

@@ -8,7 +8,7 @@
     version="0.1.0",
     author="Andrej Karpathy",
     author_email="andrej.karpathy@gmail.com",
-    description="A tiny scalar-valued autograd engine with a small PyTorch-like neural network library on top.",
+    description="A tiny autograd engine",
     long_description=long_description,
     long_description_content_type="text/markdown",
     url="https://github.com/karpathy/micrograd",
@@ -18,5 +18,6 @@
         "License :: OSI Approved :: MIT License",
         "Operating System :: OS Independent",
     ],
+    install_requires=['numpy'],
     python_requires='>=3.6',
 )