Book: add a ci chapter

Author: joshrotenberg

book/src/SUMMARY.md

@@ -13,6 +13,10 @@
     - [Pendantic]()
     - [Nursery]()
     - [Cargo]()
+- [Continuous Integration](continuous_integration/README.md)
+    - [Travis CI](continuous_integration/travis.md)
+    - [GitHub Actions](continuous_integration/github_actions.md)
+    - [Gitlab](continuous_integration/gitlab.md)
 - [Development](development/README.md)
     - [Basics](development/basics.md)
     - [Adding Lints](development/adding_lints.md)

book/src/continuous_integration/README.md

@@ -0,0 +1,5 @@
+# Continuous Integration
+
+- [Travis CI](travis.md)
+- [Github Actions](github_actions.md)
+- [Gitlab](gitlab.md)

book/src/continuous_integration/github_actions.md

@@ -0,0 +1,18 @@
+# GitHub Actions
+
+## actions-rs
+
+An easy way to get started with adding Clippy to GitHub Actions is
+the [actions-rs](https://github.com/actions-rs) [clippy-check](https://github.com/actions-rs/clippy-check):
+
+```yml
+on: push
+name: Clippy check
+jobs:
+  clippy_check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+      - name: Run Clippy
+        run: cargo clippy
+```

book/src/continuous_integration/gitlab.md

@@ -0,0 +1,3 @@
+# Gitlab
+
+***placeholder***

book/src/continuous_integration/travis.md

@@ -0,0 +1,25 @@
+# Travis CI
+
+You can add Clippy to Travis CI in the same way you use it locally:
+
+```yml
+language: rust
+rust:
+  - stable
+  - beta
+before_script:
+  - rustup component add clippy
+script:
+  - cargo clippy
+  # if you want the build job to fail when encountering warnings, use
+  - cargo clippy -- -D warnings
+  # in order to also check tests and non-default crate features, use
+  - cargo clippy --all-targets --all-features -- -D warnings
+  - cargo test
+  # etc.
+```
+
+Note that adding `-D warnings` will cause your build to fail if **any** warnings are found in your code.
+That includes warnings found by rustc (e.g. `dead_code`, etc.). If you want to avoid this and only cause
+an error for Clippy warnings, use `#![deny(clippy::all)]` in your code or `-D clippy::all` on the command
+line. (You can swap `clippy::all` with the specific lint category you are targeting.)

book/src/installation_and_usage.md

@@ -81,28 +81,8 @@ clippy-driver --edition 2018 -Cpanic=abort foo.rs
 
 Note that `rustc` will still run, i.e. it will still emit the output files it normally does.
 
-### Travis CI
-
-You can add Clippy to Travis CI in the same way you use it locally:
-
-```yml
-language: rust
-rust:
-  - stable
-  - beta
-before_script:
-  - rustup component add clippy
-script:
-  - cargo clippy
-  # if you want the build job to fail when encountering warnings, use
-  - cargo clippy -- -D warnings
-  # in order to also check tests and non-default crate features, use
-  - cargo clippy --all-targets --all-features -- -D warnings
-  - cargo test
-  # etc.
-```
+### Continuous Integration
+
+Adding Clippy to your continuous integration pipeline is a great way to automate the linting process. See the
+[Continuous Integration](continuous_integration) chapter for more information.
 
-Note that adding `-D warnings` will cause your build to fail if **any** warnings are found in your code.
-That includes warnings found by rustc (e.g. `dead_code`, etc.). If you want to avoid this and only cause
-an error for Clippy warnings, use `#![deny(clippy::all)]` in your code or `-D clippy::all` on the command
-line. (You can swap `clippy::all` with the specific lint category you are targeting.)