FAGqUduf-Ft my brand api user validations

[ericmaniraguha]

#What does this PR do?
Done with Validations for articles, Users registration, create user,

#Description of Task to be completed?

• Done with User, article Validations,
• Authentications

#How should this be manually tested?
It should be tested through postman

#Any background context you want to provide?
Unless comments

What are the relevant pivotal tracker stories?
https://trello.com/b/FAGqUduf/my-brand
https://app.getpostman.com/join-team?invite_code=27326a42f2fa0dd5309893ceba452bbc&target_code=69013d4d6e127950fa039f6fb8d2af67

#Screenshots (if appropriate)

#Questions:
N/A