await reddinx.initial(subredditName[, options])
This will save all posts from the dndmaps subreddit in the ./data folder.
A subdirectory will be created for each year since the subreddit creation, down
to the month and day. Then, a .json file will be saved for each post (the name
of the .json file is the Reddit uuid of the post).
Depending on the popularity and age of the subreddit, this can take from several minutes to several hours.
This will update your reddinx.state.js with the date of the last import, so
you'll then be able to run incremental and only update your data with the new
posts since your last import.