Added NLog, Added UserService, Added database and seed seed

Birdmap.BLL/Services/UserService.cs

@@ -0,0 +1,66 @@
+using Birdmap.BLL.Exceptions;
+using Birdmap.BLL.Interfaces;
+using Birdmap.DAL;
+using Birdmap.DAL.Entities;
+using Microsoft.EntityFrameworkCore;
+using System.Threading.Tasks;
+
+namespace Birdmap.BLL.Services
+{
+    public class UserService : IUserService
+    {
+        private readonly BirdmapContext _context;
+
+        public UserService(BirdmapContext context)
+        {
+            _context = context;
+        }
+
+        public async Task<User> CreateUserAsync(User user)
+        {
+            _context.Users.Add(user);
+            await _context.SaveChangesAsync();
+
+            return user;
+        }
+
+        public Task DeleteUserAsync(int userId)
+        {
+            return DeleteUserInternalAsync(userId);
+        }
+
+        public Task DeleteUserAsync(string username)
+        {
+            return DeleteUserInternalAsync(username);
+        }
+
+        public async Task<User> GetUserAsync(int userId)
+        {
+            return await _context.Users.SingleOrDefaultAsync(u => u.Id == userId)
+                ?? throw new EntityNotFoundException($"Cannot find user with user ID: {userId}");
+        }
+
+        public async Task<User> GetUserAsync(string username)
+        {
+            return await _context.Users.SingleOrDefaultAsync(u => u.Name == username)
+                ?? throw new EntityNotFoundException($"Cannot find user with username: {username}");
+        }
+
+        public Task UpdateUserAsync(User user)
+        {
+            _context.Users.Update(user);
+            return _context.SaveChangesAsync();
+        }
+
+        private Task DeleteUserInternalAsync(object key)
+        {
+            var user = _context.Users.Find(key);
+
+            if (user == null)
+                return Task.CompletedTask;
+
+            _context.Users.Remove(user);
+            return _context.SaveChangesAsync();
+        }
+    }
+}