Update CI

[kigawas]

related with #83

make tests pass on nightly (for now) via Travis & make builds pass on stable, beta and nightly via Github Action

[kigawas]

https://github.com/SergioBenitez/Rocket/issues/19

once this done, we can try to test it on stable, beta and nightly

[amanusk]

Is it possible to run all tests on travis and not split the tests between travis and github -ci?

[kigawas]

Is it possible to run all tests on travis and not split the tests between travis and github -ci?

you can, but what we want is to check whether it can build on stable, beta (and nightly) since rocket can only run on nightly

once rocket can build on stable, this can be removed easily by reverting PR and use travis to run tests (also okay to switch travis from github action)

[kigawas]

or you can rewrite examples to remove rocket pity that there's no "example-only dependency" in rust for now

[amanusk]

Although a bit of an overkill, we can do this for travis:

language: rust

before_script:
  - rustup component add rustfmt-preview
  - cargo fmt --all -- --check

matrix:
  include:
    - os: osx
      rust: stable
      script:
        - cargo build

    - os: osx
      rust: beta
      script:
        - cargo build

    - os: osx
      rust: nightly
      script:
        - cargo build
        - cargo test --verbose

    - os: linux
      rust: stable
      script:
        - cargo build

    - os: linux
      rust: beta
      script:
        - cargo build

    - os: linux
      rust: nightly
      script:
        - cargo build
        - cargo test --verbose

Tests only run on nightly and no need to add another ci tool (for now)