Moved registering services to separated class

SchengenVisaApi/SchengenVisaApi/DependencyInjection.cs

@@ -0,0 +1,22 @@
+using System.Reflection;
+
+namespace SchengenVisaApi
+{
+    /// Provides methods to add services to DI-container
+    public static class DependencyInjection
+    {
+        /// Add needed services
+        public static IServiceCollection RegisterServices(this IServiceCollection services)
+        {
+            services.AddControllers();
+            services.AddEndpointsApiExplorer();
+            services.AddSwaggerGen(options =>
+            {
+                var xmlFilename = $"{Assembly.GetExecutingAssembly().GetName().Name}.xml";
+                options.IncludeXmlComments(Path.Combine(AppContext.BaseDirectory, xmlFilename));
+            });
+
+            return services;
+        }
+    }
+}