I am extracting the regression results for two different groups as shown in this example below. In the `temp` data.frame i get the estimate, std.error, statistic and p-value. However, i don't get the confidence intervals. Is there a simple way to extract them as well?

```
 df <- tibble(
  a = rnorm(1000),
  b = rnorm(1000),
  c = rnorm(1000),
  d = rnorm(1000),
  group = rbinom(n=1000, size=1, prob=0.5)
)

df$group = as.factor(df$group)

temp <- df %>%
  group_by(group) %>%
  do(model1 = tidy(lm(a ~ b + c + d, data = .))) %>%   
  gather(model_name, model, -group) %>%                        
  unnest() 

```