initial backend

added backend files
Improved querying cocktails

You can now query cocktails with additional optional parameters.

Add an id to query  aspecific cocktail,
add a rating parameter to get ratings and probabilities of ratings
higher than the given number,
add a recipe parameter to get the whole recipe with ingredients

All parameters can be combined
Added tags to querying cocktails

You now get a full list of tags when querying cocktails with rating
sorted by relative amount of appearence
Restructuring Backend
Added rating

Users can now rate cocktails
Cocktail search

implemented a search function to search for cocktails by name or by
ingredients
merged backend into master