Revert "Delete appveyor.yml"

This reverts commit 3bc387b1d9.

appveyor.yml

@@ -0,0 +1,28 @@
+os: Visual Studio 2017
+
+platform:
+  - x64
+
+environment:
+  nodejs_version: "10"
+
+version: "{build}"
+
+install:
+  - ps: Install-Product node $env:nodejs_version $env:platform
+  - yarn
+  - node scripts/build-native.js
+
+build_script:
+  - yarn run build
+  - node scripts/prepackage-plugins.js
+  - node scripts/build-windows.js
+
+artifacts:
+  - path: 'dist\*.exe'
+
+cache:
+  - node_modules
+  - "*\\node_modules"
+  - "%USERPROFILE%\\.electron"
+  - "%LOCALAPPDATA%\\Yarn"