(W4) Amber & Monica (Join and share existing shopping list)

Story 4: As a user, I want to join an existing shopping list so I can share a shopping list with someone

Tasks to complete: Joining a list consists of the following:

User enters an existing token
    Show an error if the token does not exist
    Allow them to try again or start a new list
Save the token to localStorage
Show the user the existing list

AC: On the onboarding screen, the user can tap to reveal a field where they can enter an existing token Entering the token and hitting submit saves the token to localStorage, effectively giving them joint control of the list

(January 8th):

I have questions about the AC and the tasks to be completed. Once I figure these out, I think that we will be on the right track to finishing Story 4:

• Will we need 2 different components? One to accept the correct input, and one to return an error message whenever the input is not an exact match to the right information needed?
• On what page will we need to write this new code?
• How do we create a draft PR?

Edit: 1/8/2020, I created the branch for Story 4. I added a comment on the NewList.js page beforehand to ensure that I had done it correctly.