Update .travis.yml

Manishearth · Manishearth · commit 4a7cd0772eff · 2015-05-20T12:34:45.000+05:30
diff --git a/.travis.yml b/.travis.yml
@@ -1,4 +1,5 @@
 language: rust
+rust: nightly
 sudo: false
 
 script:
