run dialyzer on each build

Author: mmmries

.travis.yml

@@ -1,12 +1,18 @@
 language: elixir
 otp_release:
- - 20.1
- - 20.2
  - 20.3
 elixir:
- - 1.4.5
- - 1.5.3
- - 1.6.4
+ - 1.4
+ - 1.5
+ - 1.6
+cache:
+  directories:
+  - /home/travis/.mix
+before_script:
+ - mix dialyzer --plt
+script:
+ - mix test
+ - mix dialyzer --halt-exit-status --no-check
 after_script:
   - MIX_ENV=dev mix deps.get
   - MIX_ENV=dev mix inch.report