Create User Model

[AhmedGarcia]

Define a User schema with fields: username, email, password, friends, and booksRead.

Include validation and pre-save hooks for password hashing using bcrypt.

Export the model for use in GraphQL resolvers.

Acceptance Criteria: User schema is defined with appropriate fields and validation. Passwords are hashed before saving. Model is exported correctly.

[AhmedGarcia]

issue completed