feat/Add solution

resources/solution/back-end/.gitignore

resources/solution/back-end/config.js

resources/solution/back-end/package-lock.json

resources/solution/back-end/package.json

resources/solution/back-end/server.js

...s/solution/day-1/src/io/takima/agencymanagement/Main.java

...n/day-1/src/io/takima/agencymanagement/dao/TravelDao.java

...ion/day-1/src/io/takima/agencymanagement/dao/UserDao.java

...rc/io/takima/agencymanagement/mapper/TravelDtoMapper.java

.../src/io/takima/agencymanagement/mapper/UserDtoMapper.java

...n/day-1/src/io/takima/agencymanagement/model/Airport.java

.../day-1/src/io/takima/agencymanagement/model/Discount.java

...ay-1/src/io/takima/agencymanagement/model/HotelOffer.java

...ion/day-1/src/io/takima/agencymanagement/model/Offer.java

...src/io/takima/agencymanagement/model/PercentDiscount.java

...src/io/takima/agencymanagement/model/RestaurentOffer.java

...on/day-1/src/io/takima/agencymanagement/model/Travel.java

...tion/day-1/src/io/takima/agencymanagement/model/User.java

...1/src/io/takima/agencymanagement/model/ValueDiscount.java

...anagement/presentation/responsedto/TravelResponseDto.java