Building backend, smart contracts and administratorUI for NFT game

refer to https://dearmonster1.netlify.app/ for the frontend (still in progress of sorting out some minor details)
-this is a hybrid dApp. There is a centralised server for offchain logic and smart contracts are used to execute some onchain logic
-creation of NFT game characters and items
-game currency (DMS) creation out of scope (it has already been created)
-graphics out of scope
-gameplay front-end out of scope
-general gameplay:
1. connect metamask wallet (user account)
2. buy cave (this is an nft that will be revealed into a probabilistically determined DearMonster)
3. Use DearMonster in training ground to fight minions to win rewards and experience
4. rewards can be used to redeem DMS. experience is awarded to the DearMonster, which gives it more rewards for each fight.
5. DearMonsters can be sold and bought in the marketplace.