Database migration, repository, controller and service

Context/MyDbContext.cs

@@ -1,5 +1,5 @@
-using System;
 using Microsoft.EntityFrameworkCore;
+using PaperlessAI.Models;
 
 namespace PaperlessAI.Context;
 
@@ -19,6 +19,13 @@ public class MyDbContext : DbContext
         modelBuilder
             .UseCollation("utf8mb4_uca1400_ai_ci")
             .HasCharSet("utf8mb4");
+
+        modelBuilder
+            .Entity<PaperlessDocument>()
+            .HasIndex(x => x.DocumentId)
+            .IsUnique();
     }
 
+    public DbSet<PaperlessDocument> PaperlessDocuments { get; set; }
+
 }