Update README.md

Solves #6

README.md

@@ -9,7 +9,7 @@ A view-only (no download) link to the paper: https://rdcu.be/bItqk
 1. Make sure you have `python3.6` and the `pip` module installed. 
 We recommend using [conda environments](https://docs.conda.io/projects/conda/en/latest/user-guide/tasks/manage-environments.html).
 1. Navigate to the root folder of this repository (the same folder that contains this README file)
-and run `pip install -r requirements.txt`. Note: If you are using a conda env and any packages fail to compile during this step, you may need to first install those packages separately with `conda install package_name`. 
+and run `pip install --ignore-installed -r requirements.txt`. Note: If you are using a conda env and any packages fail to compile during this step, you may need to first install those packages separately with `conda install package_name`. 
 1. Wait for all the requirements to be downloaded and installed.
 1. Run `python setup.py install` to install this module. This will also download the Word2vec model files.
 If the download fails, manually download the [model](https://storage.googleapis.com/mat2vec/pretrained_embeddings),