PI06 i PI06-1. Docker definitions for MSSQL and Postgres. Data seeder/generator for countries and people. Entity Framework example with variants for Postgres and MSSQL

SomeOfCSharpFeatures/Extensions/Extensions.cs

@@ -0,0 +1,18 @@
+using System.Collections.Generic;
+
+namespace Extensions;
+
+public static class Extensions
+{
+  public static V GetOrCreate<K, V>(this Dictionary<K, V> dict, K key) 
+    where V : new()
+    where K: notnull  
+  {
+    if (!dict.TryGetValue(key, out V? value))
+    {
+      value = new V();
+      dict[key] = value;        
+    }
+    return value;            
+  }
+}