Update install instructions

Author: zou3519

README.md

@@ -55,19 +55,19 @@ source functorch-env/bin/activate
 Next, install one of the following following PyTorch nightly binaries.
 ```
 # For CUDA 10.2
-pip install --pre torch -f https://download.pytorch.org/whl/nightly/cu102/torch_nightly.html
+pip install --pre torch -f https://download.pytorch.org/whl/nightly/cu102/torch_nightly.html --upgrade
 # For CUDA 11.1
-pip install --pre torch -f https://download.pytorch.org/whl/nightly/cu111/torch_nightly.html
+pip install --pre torch -f https://download.pytorch.org/whl/nightly/cu111/torch_nightly.html --upgrade
 # For CPU-only build
-pip install --pre torch -f https://download.pytorch.org/whl/nightly/cpu/torch_nightly.html
+pip install --pre torch -f https://download.pytorch.org/whl/nightly/cpu/torch_nightly.html --upgrade
 ```
 If you already have a nightly of PyTorch installed and wanted to upgrade it
 (recommended!), append `--upgrade` to one of those commands.
 
 Install functorch:
 ```
 pip install ninja  # Makes the build go faster
-pip install --user "git+https://github.com/facebookresearch/functorch.git"
+pip install --user "git+https://github.com/pytorch/functorch.git"
 ```
 
 Run a quick sanity check in python:
@@ -292,7 +292,7 @@ If you use functorch in your publication, please cite it by using the following
 @Misc{functorch2021,
   author =       {Horace He, Richard Zou},
   title =        {functorch: JAX-like composable function transforms for PyTorch},
-  howpublished = {\url{https://github.com/facebookresearch/functorch}},
+  howpublished = {\url{https://github.com/pytorch/functorch}},
   year =         {2021}
 }
 ```