Add no-std category
diff --git a/Cargo.toml b/Cargo.toml
index 7bd7983..968fdca 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,7 +9,7 @@
 documentation = "https://docs.rs/async-task"
 description = "Task abstraction for building executors"
 keywords = ["futures", "task", "executor", "spawn"]
-categories = ["asynchronous", "concurrency"]
+categories = ["asynchronous", "concurrency", "no-std"]
 readme = "README.md"
 
 [target.'cfg(unix)'.dependencies]