Add AppVeyor build

Author: hazzik

appveyor.yml

@@ -0,0 +1,15 @@
+version: 5.1.0.{build}
+image: Visual Studio 2017
+environment:
+  matrix:
+  - DB: SqlServer2008
+    CONNECTION_STRING: Server=(local)\SQL2017;User ID=sa;Password=Password12!;initial catalog=nhibernate;
+  - DB: PostgreSQL
+    CONNECTION_STRING: Host=localhost;Port=5432;Username=postgres;Password=Password12!;Database=nhibernate;Enlist=true;
+services: 
+- mssql2017
+- postgresql
+build: off
+test_script:
+- cmd: powershell -noprofile -command "& ./build.ps1 -TaskList Set-Configuration,Test -properties @{\"Database\" = \"%DB%\";\"ConnectionString\"=\"%CONNECTION_STRING%\"}"
+deploy: off