CheckEmailExist is a function to check if the email already exists.

CheckAdminExist is a function to check if the Admin already exists.

CheckEmailExist is a function to check if the email already exists.

CheckUserExist is a function to check if the user already exists.

CreateAdmin is a function to create a new Admin.

CreateUser is a function to create a new user.

GetAdminByEmail is a function to get an Admin by email.

GetAdminByUserID is a function to get an Admin by userID.

GetAdminByUsername is a function to get an Admin by username.