Added Card model, updated database initialization, udated readme.

SDG-Backend-Barracuda/Models/IDatabaseModel.cs

@@ -0,0 +1,10 @@
+namespace SDG_Backend_Barracuda.Models;
+
+public interface IDatabaseModel<T, in TInput>
+{
+    Task<IEnumerable<T>> GetAllAsync();
+    Task<T?> GetByIdAsync(int id);
+    Task<T> CreateAsync(TInput input);
+    Task<T?> UpdateAsync(int id, TInput input);
+    Task<bool> DeleteAsync(int id);
+}