Documentation and started tests for auth package.

auth/errors.go

@@ -0,0 +1,17 @@
+package auth
+
+// NotAuthenticatedError is an error returned when a user is not authenticated
+type NotAuthenticatedError struct{}
+
+// Error implements the error interface.
+func (e NotAuthenticatedError) Error() string {
+	return "user not authenticated"
+}
+
+// InvalidTokenError is an error returned when an invalid token is provided
+type InvalidTokenError struct{}
+
+// Error implements the error interface.
+func (e InvalidTokenError) Error() string {
+	return "invalid token"
+}