[minor] changes in the rendering of the button group
Used switch case instead of if elseif statements for assigning the class variables.
[added-feature] Added a feature to add the active class for all the qualifiers.

Got an idea for implementing the links of the qualifiers.

Store a variable in the data for the current page called current year.

Since year is the only variable that we are confused about, it will be good enough to
use that.