APIs for premium. Billing helpers.

src/Core/Models/Api/Request/Accounts/PremiumRequestModel.cs

@@ -0,0 +1,10 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace Bit.Core.Models.Api
+{
+    public class PremiumRequestModel : PaymentRequestModel
+    {
+        [Range(0, 99)]
+        public short? AdditionalStorageGb { get; set; }
+    }
+}

src/Core/Models/Api/Request/Accounts/StorageRequestModel.cs

@@ -0,0 +1,20 @@
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+
+namespace Bit.Core.Models.Api
+{
+    public class StorageRequestModel : IValidatableObject
+    {
+        [Required]
+        public short? StroageGbAdjustment { get; set; }
+
+        public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
+        {
+            if(StroageGbAdjustment == 0)
+            {
+                yield return new ValidationResult("Storage adjustment cannot be 0.",
+                    new string[] { nameof(StroageGbAdjustment) });
+            }
+        }
+    }
+}

src/Core/Models/Api/Request/PaymentRequestModel.cs

@@ -2,7 +2,7 @@
 
 namespace Bit.Core.Models.Api
 {
-    public class OrganizationPaymentRequestModel
+    public class PaymentRequestModel
     {
         [Required]
         public string PaymentToken { get; set; }