Get data from SQL Server into a GraphQL API

Create the simplest example possible to show how to expose SQL Server data in a GraphQL API

The repo will include:

1. Scripts to create a database with a few tables
2. Sequelize: https://docs.sequelizejs.com/
3. Dataloader to streamline communication with the database: https://github.com/graphql/dataloader
4. GraphQL: https://graphql.org/
5. Graphiql: https://github.com/graphql/graphiql