added docker for test

.github/workflows/dotnet-core.yml

@@ -15,6 +15,8 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
+    - name: Launch Db for testing
+      run: docker run --name postgres -e POSTGRES_DB=mytestdb -e POSTGRES_PASSWORD=mysecretpassword -d -p 5432:5432 postgres
     - name: Setup .NET Core
       uses: actions/setup-dotnet@v1
       with: