code: public void addRoute(final TrustGraphNodeId a, final TrustGraphNodeId b) {
          addDirectedRoute(a,b);
          addDirectedRoute(b,a);
      }
docs: create a bidirectional trust link between the nodes with ids 'a' and 'b'
  
  @param a id of node that will form a trust link with 'b'
  @param b id of node that will form a trust link with 'a'