Fix integration test on appveyor

appveyor.yml

@@ -9,6 +9,9 @@ branches:
     - master
 skip_tags: true
 image: Visual Studio 2017
+environment:
+  TGS4_TEST_DATABASE_TYPE: SqlServer
+  TGS4_TEST_CONNECTION_STRING: Server=(local)\SQL2017;Database=master;User ID=sa;Password=Password12!
 configuration:
   - Debug
   - Release
@@ -24,6 +27,8 @@ cache:
   - ~\.nuget\packages -> **\*.csproj
   - C:\ProgramData\chocolatey\bin -> appveyor.yml
   - C:\ProgramData\chocolatey\lib -> appveyor.yml
+services:
+  - mssql2017
 install:
   - choco install doxygen.portable codecov graphviz.portable opencover.portable
   - nuget restore tgstation-server.sln