Add backend structure with Docker support and initial configuration files

Signed-off-by: Dmitrii <computer@yawaflua.tech>

Took 4 hours 25 minutes

backend/SpMega.Backend/Persistent/Database/AppDbContext.cs

@@ -0,0 +1,25 @@
+using Microsoft.EntityFrameworkCore;
+using MongoDB.EntityFrameworkCore.Extensions;
+using SpMega.Backend.Persistent.Models.Transactions;
+using SpMega.Backend.Persistent.Models.Users;
+
+namespace SpMega.Backend.Persistent.Database;
+
+public class AppDbContext(DbContextOptions<AppDbContext> options) : DbContext(options)
+{
+    internal DbSet<Transaction> Transactions { get; set; }
+    internal DbSet<User> Users { get; set; }
+    internal DbSet<UserSession> UserSessions { get; set; }
+
+    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
+    {
+        
+    }
+    
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        base.OnModelCreating(modelBuilder);
+        
+
+    }
+}