update README with example

[shajoezhu]

follow up #14

Update the following example with a table

library(tern.gee)
fev_data$FEV1_BINARY <- as.integer(fev_data$FEV1 > 30)
fit <- fit_gee(
  vars = list(
    response = "FEV1_BINARY",
    covariates = c("RACE", "SEX"),
    arm = "ARMCD",
    id = "USUBJID",
    visit = "AVISIT"
  ),
  data = fev_data
)

[edelarua]

• README project status updated to WIP.

[shajoezhu]

use the following example

#' library(dplyr)
#'
#' df <- fev_data %>%
#'   mutate(AVAL = as.integer(fev_data$FEV1 > 30))
#' df_counts <- df %>%
#'   select(USUBJID, ARMCD) %>%
#'   unique()
#'
#' lsmeans_df <- lsmeans(fit_gee(vars = vars_gee(arm = "ARMCD"), data = df))
#' basic_table() %>%
#'   split_cols_by("ARMCD") %>%
#'   add_colcounts() %>%
#'   summarize_gee_logistic(
#'     .in_ref_col = FALSE
#'   ) %>%
#'   build_table(lsmeans_df, alt_counts_df = df_counts)