Update README for Windows Installation

Add reference to "Build Tools for Visual Studio 2019".

Addresses issue ##34.

Author: daniel-fudge

README.md

@@ -81,23 +81,25 @@ To set up your python environment to run the code in this repository, follow the
 	activate drlnd
 	```
 
-2. Follow the instructions in [this repository](https://github.com/openai/gym) to perform a minimal install of OpenAI gym.  
+2. If running in **Windows**, ensure you have the "Build Tools for Visual Studio 2019" installed from this [site](https://visualstudio.microsoft.com/downloads/).  This [article](https://towardsdatascience.com/how-to-install-openai-gym-in-a-windows-environment-338969e24d30) may also be very helpful.  This was confirmed to work in Windows 10 Home.  
+
+3. Follow the instructions in [this repository](https://github.com/openai/gym) to perform a minimal install of OpenAI gym.  
 	- Next, install the **classic control** environment group by following the instructions [here](https://github.com/openai/gym#classic-control).
 	- Then, install the **box2d** environment group by following the instructions [here](https://github.com/openai/gym#box2d).
 
-3. Clone the repository (if you haven't already!), and navigate to the `python/` folder.  Then, install several dependencies.
-```bash
-git clone https://github.com/udacity/deep-reinforcement-learning.git
-cd deep-reinforcement-learning/python
-pip install .
-```
-
-4. Create an [IPython kernel](http://ipython.readthedocs.io/en/stable/install/kernel_install.html) for the `drlnd` environment.  
-```bash
-python -m ipykernel install --user --name drlnd --display-name "drlnd"
-```
-
-5. Before running code in a notebook, change the kernel to match the `drlnd` environment by using the drop-down `Kernel` menu. 
+4. Clone the repository (if you haven't already!), and navigate to the `python/` folder.  Then, install several dependencies.  
+    ```bash
+    git clone https://github.com/udacity/deep-reinforcement-learning.git
+    cd deep-reinforcement-learning/python
+    pip install .
+    ```
+
+5. Create an [IPython kernel](http://ipython.readthedocs.io/en/stable/install/kernel_install.html) for the `drlnd` environment.    
+    ```bash
+    python -m ipykernel install --user --name drlnd --display-name "drlnd"
+    ```
+
+6. Before running code in a notebook, change the kernel to match the `drlnd` environment by using the drop-down `Kernel` menu. 
 
 ![Kernel][image2]