public AjaxController(
     UserManager <ApplicationUser> userManager,
     SimilarityCacheModels similarityCacheModels
     )
 {
     _userManager           = userManager;
     _similarityCacheModels = similarityCacheModels;
 }
 /// <summary>
 /// Constructor
 /// </summary>
 /// <param name="maxLevel">Id of the signed in user</param>
 /// <param name="numberOfNSimilarNeighbors">Number of similar neighbors to take</param>
 /// <param name="numberOfNeighborsForNextLevel">Number of neighbors for next speading level</param>
 /// <param name="model">Data model provides similarity of books</param>
 /// <returns>New instance</returns>
 public RecommenderSpreadingActivation(int maxLevel, int numberOfSimilarNeighbors,
                                       int numberOfNeighborsForNextLevel, SimilarityCacheModels simCacheModel)
 {
     this.maxLevel = maxLevel;
     this.numberOfSimilarNeighbors      = numberOfSimilarNeighbors;
     this.numberOfNeighborsForNextLevel = numberOfNeighborsForNextLevel;
     this.simCacheModel = simCacheModel;
 }