sudo: false
language: erlang
install: 'true'
otp_release:
- 19.0
- 18.0
script: "./elvis rock && ./rebar3 do dialyzer, eunit"

sudo: false
language: erlang
install: 'true'
before_script:
- wget https://s3.amazonaws.com/rebar3/rebar3
- chmod +x rebar3
env: PATH=$PATH:.
cache:
  directories:
  - $HOME/.cache/rebar3/
otp_release:
- 19.0
- 18.0
script: "./elvis rock && rebar3 do dialyzer, eunit"

Use latest rebar3 and persist cache on Travis
Use latest rebar3 and persist cache on Travis

It might be wise to get rid of ./rebar3 to avoid inconsistent results.
