Add github actions

.github/workflows/continuous_testing.yaml

@@ -0,0 +1,21 @@
+name: test
+on: push
+
+jobs:
+  build_and_test:
+    name: test
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macOS-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@master
+      - name: Install cargo
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          override: true
+      - name: Run test
+        uses: actions-rs/cargo@v1
+        with:
+          command: test

README.md

@@ -1,6 +1,7 @@
 # mos6502
 
-[![Build Status](https://travis-ci.org/mre/mos6502.svg?branch=master)](https://travis-ci.org/mre/mos6502)
+[![Build Status](https://travis-ci.org/mre/mos6502.svg?branch=master)](https://travis-ci.org/mre/mos6502) 
+![](https://github.com/mre/mos6502/workflows/test/badge.svg)
 
 An emulator for the [MOS 6502 CPU](https://en.wikipedia.org/wiki/MOS_Technology_6502) written in Rust.  
 This started off as a fork of [amw-zero/6502-rs](https://github.com/amw-zero/6502-rs),