Add GitHub actions workflow

Author: phil-opp

.github/workflows/build.yml

@@ -0,0 +1,65 @@
+name: Build
+
+on:
+  push:
+    branches:
+      - 'master'
+    tags:
+      - '*'
+  schedule:
+    - cron: '40 5 * * *'   # every day at 5:40
+  pull_request:
+
+jobs:
+  test:
+    name: "Test"
+
+    strategy:
+      matrix:
+        platform: [
+          ubuntu-latest,
+          macos-latest,
+          windows-latest
+        ]
+
+    runs-on: ${{ matrix.platform }}
+    timeout-minutes: 15
+
+    steps:
+    - name: "Checkout Repository"
+      uses: actions/checkout@v1
+
+    - name: Install Rustup
+      run: |
+        curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain nightly
+        echo ::add-path::$HOME/.cargo/bin
+      if: runner.os == 'macOS'
+
+    - name: Set Rustup profile to minimal
+      run: rustup set profile minimal
+
+    - name: "Print Rust Version"
+      run: |
+        rustc -Vv
+        cargo -Vv
+
+    - name: "Run cargo build"
+      run: cargo build
+
+    - name: "Build with `alloc_ref` feature"
+      run: cargo build --features alloc_ref
+
+    - name: "Run cargo test"
+      run: cargo test
+
+    - name: 'Deny Warnings'
+      run: cargo rustc -- -D warnings
+
+  check_formatting:
+    name: "Check Formatting"
+    runs-on: ubuntu-latest
+    timeout-minutes: 2
+    steps:
+    - uses: actions/checkout@v1
+    - run: rustup install nightly
+    - run: cargo +nightly fmt -- --check