removeRing(ringId) {
    this.rings = this.rings.filter(function (item) {
      return item.id !== ringId;
    }); // Also remove ring connections involving this ring

    this.ringConnections = this.ringConnections.filter(function (item) {
      return item.firstRingId !== ringId && item.secondRingId !== ringId;
    }); // Remove the ring as neighbour of other rings

    for (var i = 0; i < this.rings.length; i++) {
      let r = this.rings[i];
      r.neighbours = r.neighbours.filter(function (item) {
        return item !== ringId;
      });
    }
  }
Removes a ring from the array of rings associated with the current molecule.

@param {Number} ringId A ring id.