feat: token based authentication, authenticate route, token storage

projects/greenlight/internal/data/users.go

@@ -39,6 +39,14 @@ type password struct {
 	hash      []byte
 }
 
+// Declare a new AnonymousUser variable.
+var AnonymousUser = &User{}
+
+// Check if a User instance is the AnonymousUser.
+func (u *User) IsAnonymous() bool {
+	return u == AnonymousUser
+}
+
 // The Set() method calculates the bcrypt hash of a plaintext password, and stores both
 // the hash and the plaintext versions in the struct.
 func (p *password) Set(plaintextPassword string) error {