travis: Also build Rust stable
diff --git a/.travis.yml b/.travis.yml
index c4ca38d..5c1cc7c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,7 @@
 language: rust
 rust:
   - 1.0.0
+  - stable
   - beta
   - nightly
 sudo: false