Picker Randomly pick a channel member to complete a task

Picker randomly picks a channel member to complete a task, such as pick where to eat for lunch, perform a code review, or any custom task you can think of. Here are some examples:/pick cr http://github.com/repo/example
 — Hey @osmyn, you have been picked to do a code review: http://github.com/repo/example/pick task Replenish the snacks
 — Hey @osmyn, you have been picked to complete the task: Replenish the snacks/pick lu Somewhere fast
 — Hey @osmyn, you have been picked to pick a place for lunch: Somewhere fast/pick ot Someone needs to pick up the dog from the vet
 — Hey @osmyn, you have been picked to to another thing: Someone needs to pick up the dog from the vet