add functions for changing order

[woylie]

• swap([:pets, 3], 5)
• move_up([:pets, 3])
• move_down([:pets, 3])
• move_to([:pets, 3], 5])

[jacmacmod]

how do we swap one pet's toys with another pet's toys at specific positions

[%Pet{id: 1, toys: [a, b]}, %Pet{id: 2, toys: [c, d]}]

[woylie]

Probably swap([:owners, 2, :pets, 3], [:owners, 4, :pets, 1]).