Enable Travis CI caching

Nemo157 · web-flow · commit a097f86c72d3 · 2018-08-03T13:39:43.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -2,6 +2,7 @@ language: rust
 rust:
   - nightly
 sudo: false
+cache: cargo
 
 matrix:
   include:
