Instagram seems to be on a feature-rollout spree. It hasn't been many days since the new Type feature was released, where users could change fonts of the written text. Before that, it introduced GIF support.
Now, Instagram has introduced a new feature which lets you Reshare to Stories. Now in order to reshare the user must have a public account as it will not work with private accounts.
According to Instagram "other people can add your posts to their stories. Your username will always appear with your post."
This is similar to Regram, a third party app, which would help the user repost pictures or videos on the photo-sharing platform.