Added synonyms in order to also find 'bourbon' when looking for 'whiskey'
or 'cognac' when looking for 'brandy' and so on, but not vice versa.

Therefore a list of synonyms was added and whenever a listed word appears in
an ingredient of a recipe when building the index, its synonym is appended.
Added definition for 'rhum' -> 'rum' to the word forms list.
Added definition for 'akvavit' -> 'aquavit' to the word forms list.
Since ginger beer has nothing to with beer, don't show recipes with ginger
beer anymore when searching for just 'beer', but show them when searching
for 'ginger' or 'ginger beer'.