Refactored to use postgres for production and sqlite for development

appsettings.json

@@ -1,6 +1,9 @@
 {
+  "Database": {
+    "Provider": "Postgres"
+  },
   "ConnectionStrings": {
-    "DefaultConnection": "DataSource=app.db;Cache=Shared"
+    "DefaultConnection": "Host=localhost;Port=5432;Database=example_prod;Username=postgres;Password=postgres"
   },
   "Logging": {
     "LogLevel": {