Final Exercise

For this final exercise, you're going to build a sports league registration form. Here's your opportunity to practice everything we've learned together in one application so you can really master your skills and see how it all connects.

Exercise Instructions
1. Initialize the form with FormBuilder, using at least one nested FormGroup of your choosing
2. Allow the user to invite as many teammates as they want by hooking up a FormArray. Allow them to add & remove emails
3. Bind shirt size selection to update the control’s value
4. Add built-in validators for controls with placeholders of “required”, shirt size, and require the waiver has been agreed to
5. Create a custom validator so last name can’t include “null” in it
6. Show error messages & use getters for shorthand
7. Update at least 1 validator dynamically. For example, if the team selected is “Other”, require a new team name to be defined, otherwise it's optional

Link to Exercise: https://stackblitz.com/fork/rxngforms-finalexercise