public void InvolveUser(IUser user, Contributions contribution)
{
if(!user.IsContributingAs(contribution))
{
throw new ArgumentException(String.Format("User {0} is not a {1}.", user, contribution), "contribution");
}
lock (involvements)
{
if (!IsUserInvolvedAs(user, contribution))
{
involvements.Add(new KeyValuePair<IUser, Contributions>(user, contribution));
}
}
}
