Fix database schema

Entities/Board.cs

@@ -6,6 +6,6 @@
 
         public virtual ICollection<User>? Users { get; set; } = new HashSet<User>();
 
-        public virtual ICollection<Card>? Cards { get; set; } = new HashSet<Card>(); 
+        public virtual ICollection<Column>? Columns { get; set; } = new HashSet<Column>(); 
     }
 }

Entities/Card.cs

@@ -4,12 +4,11 @@
     {
         public string Name { get; set; }
         public string Description { get; set; }
-        public string Column { get; set; }
         public int SenderId { get; set; }
-        public int BoardId { get; set; }
+        public int ColumnId { get; set; }
 
         public virtual User Sender { get; set; }
-        public virtual Board Board { get; set; }
+        public virtual Column Column { get; set; }
 
         public virtual ICollection<Comment> Comments { get; set; } = new HashSet<Comment>();
     }

Entities/Column.cs

@@ -0,0 +1,12 @@
+namespace NG_2023_Kanban.Entities
+{
+    public class Column : BaseEntity
+    {
+        public string Name { get; set; }
+        public int BoardId { get; set; }
+
+        public virtual Board Board { get; set; }
+
+        public virtual ICollection<Card>? Cards { get; set; } = new HashSet<Card>();
+    }
+}

Entities/User.cs

@@ -10,6 +10,7 @@
         public bool IsAdmin { get; set; }
 
         public virtual ICollection<Board>? Boards { get; set; } = new HashSet<Board>();
+        public virtual ICollection<Card>? Cards { get; set; } = new HashSet<Card>();
         public virtual ICollection<Comment>? Comments { get; set; } = new HashSet<Comment>();
     }
 }

EntityConfiguration/CardConfiguration.cs

@@ -17,13 +17,16 @@ namespace NG_2023_Kanban.EntityConfiguration
             builder.Property(x => x.Description).IsRequired();
             builder.Property(x => x.Description).HasMaxLength(100);
 
-            builder.Property(x => x.Column).IsRequired();
+            builder
-            builder.Property(x => x.Column).HasMaxLength(100);
+                .HasOne(x => x.Sender)
+                .WithMany(x => x.Cards)
+                .HasForeignKey(x => x.SenderId)
+                .HasPrincipalKey(x => x.Id);
 
             builder
-                .HasOne(x => x.Board)
+                .HasOne(x => x.Column)
                 .WithMany(x => x.Cards)
-                .HasForeignKey(x => x.BoardId)
+                .HasForeignKey(x => x.ColumnId)
                 .HasPrincipalKey(x => x.Id);
         }
     }

EntityConfiguration/ColumnConfiguration.cs

@@ -0,0 +1,27 @@
+using NG_2023_Kanban.Entities;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+
+namespace NG_2023_Kanban.EntityConfiguration
+{
+    public class ColumnConfiguration : IEntityTypeConfiguration<Column>
+    {
+        public void Configure(EntityTypeBuilder<Column> builder)
+        {
+            builder.HasIndex(x => x.Id);
+            builder.Property(x => x.Id).IsRequired();
+
+            builder.Property(x => x.Name).IsRequired();
+            builder.Property(x => x.Name).HasMaxLength(100);
+
+            builder.Property(x => x.Board).IsRequired();
+            builder.Property(x => x.Board).HasMaxLength(100);
+
+            builder
+                .HasOne(x => x.Board)
+                .WithMany(x => x.Columns)
+                .HasForeignKey(x => x.BoardId)
+                .HasPrincipalKey(x => x.Id);
+        }
+    }
+}