# Functions
AllStrategies returns all strategies.
AllUsers returns all users.
NewInvitation returns a new Invitation struct.
UserFromID finds user by user ID.
# Structs
Invitation is a struct for describing invitation.
Stock is a struct describing each stock item.
StockPrice is a struct describing price of the stock.
User is a struct for describing users.
UserStock is a struct describing the users' stock strategy.
WatchingStock is a struct for describing if the stock item is being watched or not.
# Type aliases
Market is an enum type representing the type of the stock market.