WIP GitHub Actions for CI

.github/workflows/build-test.yml

@@ -0,0 +1,49 @@
+name: Build & Test
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: '*'
+
+jobs:
+  build:
+
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ ubuntu-latest, macos-latest, windows-latest ]
+
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+    - uses: actions/checkout@v2
+
+    ## Cache steps
+
+    - name: Cache cargo registry
+      uses: actions/cache@v1
+      with:
+        path: ~/.cargo/registry
+        key: ${{ runner.os }}-cargo-registry-${{ hashFiles('**/Cargo.lock') }}
+
+    - name: Cache cargo index
+      uses: actions/cache@v1
+      with:
+        path: ~/.cargo/git
+        key: ${{ runner.os }}-cargo-index-${{ hashFiles('**/Cargo.lock') }}
+
+    - name: Cache cargo build
+      uses: actions/cache@v1
+      with:
+        path: target
+        key: ${{ runner.os }}-cargo-build-target-${{ hashFiles('**/Cargo.lock') }}
+
+    ## Build and run steps
+
+    - name: Build
+      run: cargo build --verbose
+
+    - name: Test
+      run: cargo test --verbose

README.md

@@ -5,6 +5,9 @@ Welcome to the home page for the ICU4X-SC.  We are a subcommittee of ICU-TC in t
 
 Please subscribe to this repository to participate in discussions.  If you would like to join the core development team, apply to join [our mailing list](https://groups.google.com/a/unicode.org/forum/#!forum/omnicu-core).
 
+![build & test](https://github.com/unicode-org/icu4x/workflows/Build%20&%20Test/badge.svg)
+
+
 ## Charter
 
 *For the full charter, including answers to frequently asked questions, see [charter.md](docs/charter.md).*