Apostrophes can be used to mark abbreviations and contractions. So 'Gram is an abbreviation since the full name of the city is "Gurugram". Calling it 'Gram Culture is fitting since it calls attention to the name change from -gaon to -gram.
So the author believes they need to develop a culture that the author is calling 'Gram Culture.
Now, part of the sense of "culture" here is
a : enlightenment and excellence of taste acquired by intellectual and aesthetic training
b : acquaintance with and taste in fine arts, humanities, and broad aspects of science as distinguished from vocational and technical skills
In other words, there should be a level sophistication associated with this so-called Gram Culture.
believing that microbreweries are really art galleries, minus the art.
I believe the author is making a joke. He is saying that microbreweries do not count as art. So having them as part of the Gram Culture does not really add sophistication to the culture.
One of the definitions of hurrah is
hubbub; commotion; fanfare
It is noun, but by writing "brand-hurrahing", I think the author is saying something like "making a commotion about brand(s)", or simply "brand advertising".