handle "class"-like outcome names and levels

[simonpcouch]

Closes #125.

library(tidymodels)
library(stacks)

x <- tibble::tibble(
  class = sample(c("class_1", "class_2"), 100, replace = TRUE),
  a = rnorm(100),
  b = rnorm(100)
)

res <- tune_grid(
  logistic_reg(engine = 'glmnet', penalty = tune(), mixture = 1),
  preprocessor = recipe(class ~ ., x),
  resamples = vfold_cv(x, 2),
  grid = 2,
  control = control_stack_grid()
)

stacks() %>%
  add_candidates(res)
#> # A data stack with 1 model definition and 1 candidate member:
#> #   res: 1 model configuration
#> # Outcome: class (factor)

^{Created on 2022-05-03 by the reprex package (v2.0.1)}

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