Add tests for targeted version (1.28.0)

.gitlab-ci.yml

@@ -5,15 +5,21 @@ variables:
 before_script:
   - apt-get update -qq
   - apt-get install -qq build-essential curl git
+cache:
+  paths:
+    - cargo/
+    - target/
 
 linux:
+  image: 'rust:1.28.0'
   script:
     - cargo build
     - make tests
-  cache:
-    paths:
-      - cargo/
-      - target/
+
+linux:stable:
+  script:
+    - cargo build
+    - TOOLCHAIN=stable make tests
 
 redox:
   variables:
@@ -28,7 +34,3 @@ redox:
     - rustup target add x86_64-unknown-redox
   script:
     - make REDOX=1
-  cache:
-    paths:
-      - cargo/
-      - target/