gistfile1.rb

# Not so good
i=0
while i<=colnum-1 do                                #adding the columns
	database.alter_table tabname.to_sym do
		add_column colnames[i], String
		i+=1
	end
end

# Better

colnames.map do |colname|                                #adding the columns
	database.alter_table tabname.to_sym do
		add_column colname, String
	end
end