Create New User API

[AlexanderLiteplo]

Should create a folder in bucket "project-data-69/user_id" where user_id is their email address.

Should create an entry in the DynamoDB table with the fields:
user_id: "panda@example.com"
projects: [project_id, ...]
has_premium: true

[AlexanderLiteplo]

user_id passed in as a param to the api