/// <summary>
/// Relates the root node with adjacent ones.
/// </summary>
/// <param name="node">The root node of a subtree.</param>
/// <returns>The task</returns>
public async Task RelatePath(NodeModel nodeModel)
{
var node = AutoMapper.Mapper.Map <NodeEntity>(nodeModel);
var adjacentNodes = AutoMapper.Mapper.Map <List <NodeEntity> >(nodeModel.AdjacentNodes);
await nodeRepository.AddOrUpdateAsync(node);
await nodeRepository.AdjacentNodesIfDoNotExistAsync(nodeModel.Id, adjacentNodes);
}