After graduating Launch Academy you get a job working for Globo Gym. They want you to build a light-weight, lean, and agile Sinatra application to handle all their memberships. White Goodman understands the importance of using an ORM to model your data and he has concluded that Active Record is the most badass one around. Currently, Globo Gym has over 20 locations and is slowly putting the Average Guys gym out of business. (which is probably why they can afford to hire you)
Create the ER Diagram and associations for Globo Gym's new application. There will be multiple gyms using the application and users memberships are only available at one gym. Think about what types of tables you will need to create this application. Think about what different columns you will need in each table.