Release for sharing large data assets associated with repository

This is an alpha version that allows us to share large files that we had previously not been able to upload. Github has a 50 MB limit on commit file sizes which is why some of the larger shapefiles were not uploaded with previous iterations of the repository. This release workflow allows us to upload and track these large files by using the piggback R package.

Some of the datasets used in this repository are under a Data Use agreement and will not be made public. For example, we extensively use the American Hospital Association datasets(https://www.ahadata.com/aha-annual-survey-database-asdb/) to obtain hospital coordinates. If the user has access to these data through their organization, they would need to change the paths and point them to the corresponding data storage location. Parts of the code that use these datasets will be explicitly annotated to mitigate confusion.

For publicly available data, we describe how to obtain and preprocess them. For example, we use the CMS Hospital Service Area Data that can be downloaded from: https://www.cms.gov/Research-Statistics-Data-and-Systems/Statistics-Trends-and-Reports/Hospital-Service-Area-File/index.html. The R script: "R/read-and-tidy-cms-hospital-service-areas.R" contains detailed steps on how to convert this raw zip-level data to county-level data.