[SAVING] LIST cannot be serialized because it does not have a default public constructor

Hi. I tried to follow some tutorials about saving and creating list.

Imagine a Cookie Clicker with buyable buildings, that's what I wanted.

So I created a list with a string (Name of the building) and an int (Amount of buildings)

     public class GoatList : IComparable<GoatList>
     {
         string name;
         int owned;
 
         public GoatList(string newName, int newOwned)
         {
             name = newName;
             owned = newOwned;
         }
 
         public int CompareTo(GoatList other)
         {
             if (other == null)
             {
                 return 1;
             }
 
             //Return the difference in power.
             return owned - other.owned;
         }
     }

(The code is not finished, created with the Unity Tutorial)

And then I wanted to save this to the player's savestate :

     public List<savemanager.GoatList> goat;

The problem is that I'm having this error :

 InvalidOperationException: savemanager+GoatList cannot be serialized because it does not have a default public constructor
 System.Xml.Serialization.ReflectionHelper.CheckSerializableType (System.Type type, Boolean allowPrivateConstructors)
 System.Xml.Serialization.XmlReflectionImporter.ImportClassMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
 System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
 Rethrow as InvalidOperationException: There was an error reflecting type 'savemanager+GoatList'.
 System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
 System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Type type, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
 System.Xml.Serialization.XmlReflectionImporter.ImportListMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace, System.Xml.Serialization.XmlAttributes atts, Int32 nestingLevel)
 System.Xml.Serialization.XmlReflectionImporter.ImportListMapping (System.Type type, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace, System.Xml.Serialization.XmlAttributes atts, Int32 nestingLevel)
 System.Xml.Serialization.XmlReflectionImporter.CreateMapMember (System.Type declaringType, System.Xml.Serialization.XmlReflectionMember rmember, System.String defaultNamespace)
 System.Xml.Serialization.XmlReflectionImporter.ImportClassMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
 Rethrow as InvalidOperationException: There was an error reflecting field 'goat'.
 System.Xml.Serialization.XmlReflectionImporter.ImportClassMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
 System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
 Rethrow as InvalidOperationException: There was an error reflecting type 'savestate'.
 System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Xml.Serialization.TypeData typeData, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
 System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping (System.Type type, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
 System.Xml.Serialization.XmlSerializer..ctor (System.Type type, System.Xml.Serialization.XmlAttributeOverrides overrides, System.Type[] extraTypes, System.Xml.Serialization.XmlRootAttribute root, System.String defaultNamespace)
 System.Xml.Serialization.XmlSerializer..ctor (System.Type type)
 helper_script.Deserialize[savestate] (System.String toDeserialize) (at Assets/Scripts/helper_script.cs:18)
 savemanager.Load () (at Assets/Scripts/savemanager.cs:29)
 savemanager.Awake () (at Assets/Scripts/savemanager.cs:15)
 

How can I fix this ?

Sorry for the messy code, I'm still learning.