The Path of the Flask
To benefit from the powers of Rage, one does not have to hail from the uncivilized lands, or from the frontiers. That beast lives in all of us, and while some use their totemic heritage to call it out, that is only one of the methods. Many has discovered the Path of the Flask, simply by drinking a lot of alchoholic drinks, and they felt that their fighting prowess grew greatly under the influence of such beverages.
Starting at 3rd level, you realize you can make your rage last longer, and your strikes to become more powerful by consuming alchoholic drinks beforehand. If you enter a rage while influenced by alchohol, your rage lasts twice the normal amount, and you deal 1d6 extra damage to your enemies. You can only deal this damage once per round.
Beginning at 3rd level, when you take the Path of the Flask, you gain an addiction to alchohol. At least once a day you must consume alchoholic beverages. After a day without such drinks you gain disadvantage on all ability checks. This can only be removed by drinking alchohol.
Poison of choice
Beginning at 6th level your consumption of alchohol made you more resilient to poison based effects. You gain resistance to poison damage, and you roll your saving throws against poison with an advantage. Furthermore you can never black out from drinking too much, and you keep your ability to act even when you are completely intoxicated
Beginning at 10th level your drinking habit enhances your rage further. Your inability to feel pain while under alchoholic influence, your "bavery" gained from the bottle, and your reckless deceison making makes you unstoppable. If you rage while intoxicated, you gain resistance to all kind of damage, and you roll all saving throws with advantage
Chalice of Vigor
Beginning at 14th level you can gain refreshment from drinking. While raging you can consume any alchoholic drink as a bonus action to regain hit points equal to your twice your Barbarian level + your Constitution modifier. You regain the use of this ability after finishing a short rest.