Setting up multiple build targets for travis

.travis.yml

@@ -5,9 +5,8 @@ branches:
   only:
     - master 
 
-matrix:
-  include:
-    - os: linux
+os:
+  - linux
     addons:
       apt:
         sources:
@@ -15,7 +14,10 @@ matrix:
         packages:
           - libc++-dev
           - ninja-build
-        env: CMAKE_BUILD_TYPE=DEBUG
+
+env:
+  - CMAKE_BUILD_TYPE=DEBUG
+  - CMAKE_BUILD_TYPE=RELEASE
 
 # Build steps
 script: