In a saucepan over medium heat combine the cranberries, sugar and fresh lime juice;bring to a boil. Reduce heat and simmer until all cranberries burst. remove from heat, allow to cool completely. Once the mixture has cooled completely, strain using back of spoon to extract as much liquid from cranberries as possible. Stir in vodka and lime zest then cover and place in fridge to infuse for up to one week. When ready to package, remove lime zest and pour into jars or bottles.