//Add Vanilla Bookshelf to bookshelf oredict
val bookshelf = <ore:bookshelf>;
bookshelf.add(<minecraft:bookshelf>);

//remove and replace Akashic tome recipe with oredict bookshelf
recipes.removeShapeless(<akashictome:tome>);
recipes.addShapeless(<akashictome:tome>, [<minecraft:book>, <ore:bookshelf>]);