Test rust 1.15.0

.travis.yml

@@ -2,10 +2,12 @@ sudo: false
 language: rust
 cache: cargo
 
-# run builds for all the trains (and more)
+# Run builds for all the trains (and more).
+# Remember to update the numbers in travis.sh too.
 rust:
   - stable
   - nightly
+  - 1.15.0
   - 1.16.0
   - 1.17.0
   - beta

travis.sh

@@ -37,7 +37,7 @@ else
     channel test
     channel test --features preserve_order
 
-    for CHANNEL in stable 1.12.0 1.13.0 beta; do
+    for CHANNEL in stable 1.15.0 1.16.0 1.17.0 beta; do
         channel clean
         channel build
         channel build --features preserve_order