feat: add database connections, initial migration and early CLI tooling

Entities/Genre.cs

@@ -0,0 +1,10 @@
+namespace Shadow.Entities;
+public class Genre
+{
+	required public int Id { get; set; }
+	required public string Name { get; set; }
+	required public string NormalizedName { get; set; }
+
+	// List of genre-song pairs of a given genre
+	public List<GenreSong> GenreSongPair { get; set; } = [];
+}