Adding an objective

Describes adding an objective function to the application.

The objective is to minimize costs of supplying cars from factories to showrooms, It is added to the model in these lines:

    IloExpr obj(env);
    for(i = 0; i < nbSupply; i++){
      obj += IloSum(y[i]);
    }

    model.add(IloMinimize(env, obj));
    obj.end();