Add caching for .cargo directory and create CI workflow

.github/actions/cache_cargo/action.yaml

@@ -0,0 +1,17 @@
+name: cache_cargo
+description: caching .cargo directory
+runs:
+  using: composite
+
+  steps:
+    - name: Cache cargo registry
+      uses: actions/cache@v2
+      with:
+        path: |
+          ~/.cargo/bin/
+          ~/.cargo/registry/index/
+          ~/.cargo/registry/cache/
+          ~/.cargo/git/db/
+          server/target/
+        key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+        restore-keys: ${{ runner.os }}-cargo-

.github/workflows/ci.yaml

@@ -0,0 +1,45 @@
+on: push
+
+jobs:
+  build_cache:
+    runs-on: ubuntu-latest
+    env:
+      RUSTC_FORCE_INCREMENTAL: 1
+    steps:
+      - uses: actions/checkout@v2
+      - uses: ./.github/actions/cache_cargo
+      - name: build
+        run: cargo build
+
+  fmt:
+    runs-on: ubuntu-latest
+    needs: build_cache
+    steps:
+      - uses: actions/checkout@v2
+      - run: rustup component add rustfmt
+      - uses: ./.github/actions/cache_cargo
+      - name: fmt
+        run: cargo fmt --all -- --check
+
+  clippy:
+    runs-on: ubuntu-latest
+    env:
+      RUSTC_FORCE_INCREMENTAL: 1
+    needs: build_cache
+    steps:
+      - uses: actions/checkout@v2
+      - run: rustup component add clippy
+      - uses: ./.github/actions/cache_cargo
+      - name: clippy
+        run: cargo clippy --all-targets --all-features -- -D warnings
+
+  test:
+    runs-on: ubuntu-latest
+    env:
+      RUSTC_FORCE_INCREMENTAL: 1
+    needs: build_cache
+    steps:
+      - uses: actions/checkout@v2
+      - uses: ./.github/actions/cache_cargo
+      - name: test
+        run: cargo test --all -- --nocapture