Add companies by book.

Cicm.Database/Models/CompaniesByBook.cs

@@ -0,0 +1,18 @@
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace Cicm.Database.Models
+{
+    public class CompaniesByBook : BaseModel<long>
+    {
+        public int  CompanyId { get; set; }
+        public long BookId    { get; set; }
+        [Column(TypeName = "char(3)")]
+        [Required]
+        public string RoleId { get; set; }
+
+        public virtual DocumentCompany Company { get; set; }
+        public virtual Book            Book    { get; set; }
+        public virtual DocumentRole   Role    { get; set; }
+    }
+}