Role.cs

    public class Role
    {
        public static Role Author { get; } = new Role(0, "Author");
        public static Role Editor { get; } = new Role(1, "Editor");
        public static Role Administrator { get; } = new Role(2, "Administrator");
        public static Role SalesRep { get; } = new Role(3, "Sales Representative");

        private Role(int val, string name)
        {
            Value = val;
            Name = name;
        }

        [Obsolete("EntityFramework's best friend", true)]
        private Role()
        {
            // required for EF
        }

        private int _value;
        public int Value
        {
            get { return _value; }
            private set
            {
                Name = FromValue(value).Name;
                _value = value;
            }
        }

        public string Name { get; private set; }

        public static IEnumerable<Role> List()
        {
            return new[] { Author, Editor, Administrator, SalesRep };
        }

        public static Role FromString(string roleString)
        {
            return List().FirstOrDefault(r => String.Equals(r.Name, roleString, StringComparison.OrdinalIgnoreCase));
        }

        public static Role FromValue(int value)
        {
            return List().FirstOrDefault(r => r.Value == value);
        }

        protected bool Equals(Role other)
        {
            return _value == other._value;
        }

        public override bool Equals(object obj)
        {
            if (ReferenceEquals(null, obj)) return false;
            if (ReferenceEquals(this, obj)) return true;
            if (obj.GetType() != this.GetType()) return false;
            return Equals((Role) obj);
        }

        public override int GetHashCode()
        {
            return _value;
        }

        public static bool operator ==(Role left, Role right)
        {
            return Equals(left, right);
        }

        public static bool operator !=(Role left, Role right)
        {
            return !Equals(left, right);
        }
    }

One suggestion, I updated the public constructor to set the private backing field _value instead of the property, otherwise I think you will get cyclical dependencies:

    private Role(int val, string name)
    {
        _value = val;
        Name = name;
    }