Initial split of the modules

NadekoBot.Core/Services/Database/Models/CommandCost.cs

@@ -0,0 +1,21 @@
+namespace NadekoBot.Services.Database.Models
+{
+    public class CommandCost : DbEntity
+    {
+        public int Cost { get; set; }
+        public string CommandName { get; set; }
+
+        public override int GetHashCode() =>
+            CommandName.GetHashCode();
+
+        public override bool Equals(object obj)
+        {
+            var instance = obj as CommandCost;
+
+            if (instance == null)
+                return false;
+
+            return instance.CommandName == CommandName;
+        }
+    }
+}