Implement Customer model

[iameo]

What Functionality / Service / Endpoint would you like to add?
The Customer model

Describe this Functionality / Service / Endpoint, and process
The customer model to handle customers.

• Create a Customer class in customer.py (models)
• Define fields/attributes in Customer class
• Customer class can now be imported when needed to query the database using ORM.

Slack username
@OEMMANUEL

[iameo]

Kindly assign this to me and then check my fix.