Yoga is much more than a workout. It's a way of life. The physical practice, asana, is only part of the picture.

Yama and Niyama
There are certain guidelines a yogi looks to, in order to live a happy and healthy life called yama and niyama. Yama are ethical disciplines of morality for society. Niyama are rules of conduct as they apply to the individual. They are not Commandments. Don't worry, if you don't follow them perfectly you won't burn in hell. They simply suggest a way of being the best person you can be. I found that following these guidelines was extremely helpful in conquering my craving for alcohol. There are 5 yama and 5 niyama.

Yama
Ahimsa - non violence - as in stop killing yourself with vodka.
Satya - truthfulness - as in don't lie to yourself that you don't have a problem.
Asteya - non stealing, non coveting - as in not robbing yourself of health and vitality. As in being you rather than comparing yourself to others.
Brahmacharya - self restraint, chastity - as in don't be a drunken slut.
Aparigraha - greedlessness, non hoarding - as in get rid of what's not helping you - namely dependence on alcohol and/or drugs.

Niyama
Saucha - purity - pure as in clean. As in not reeking of whiskey.
Santosa - contentment - as in being content to just be... without beer.
Tapas - burning effort to reunite with ones divine nature - as in burning effort to get healthy, strong and sane.
Svadhyaya - self study - as in figure out why you drink so you can deal with it instead of drowning it in alcohol. Write in your journal. Go to therapy.
Isvara pranidhana - devotional offering - as in doing yoga as an offering to the God within you.

As you begin examining the reasons why you drink, the effects your drinking has on yourself and others and the strength of character it takes to refrain from getting loaded, the importance of yama and niyama will become clear.

You can learn more about yama and niyama in the classic "Light on Yoga" by B.K.S. Iyengar.

Another great way to learn about living "yogically" is to read "The Bhagavad Gita" (The song of God).