smoothen registration process and first experience

app/controllers/confirmations_controller.rb

@@ -0,0 +1,40 @@
+class ConfirmationsController < Devise::ConfirmationsController
+  def show
+    self.resource = resource_class.confirm_by_token(params[:confirmation_token])
+    yield resource if block_given?
+
+    if Conference.all.count == 1 && Conference.first.registration_open?
+        @conference = Conference.first
+        @conference.registrations.create!(user_id: self.resource.id)
+        @redirection_path = register_conference_path(@conference.short_title)
+    end
+
+    sign_in resource if resource
+
+    if resource.errors.empty?
+      if @redirection_path.blank?
+        set_flash_message(:notice, :confirmed) if is_flashing_format?
+      else
+        set_flash_message(:notice, :confirmed_registered) if is_flashing_format?
+      end
+      respond_with_navigational(resource){ redirect_to after_confirmation_path_for(resource_name, resource) } and return
+    else
+      respond_with_navigational(resource.errors, status: :unprocessable_entity){ render :new } and return
+    end
+  end
+
+  private
+
+  def after_confirmation_path_for(resource_name, resource)
+
+    if @redirection_path.blank?
+      if signed_in?
+        signed_in_root_path(resource)
+      else
+        new_session_path(resource_name)
+      end
+    else
+      @redirection_path
+    end
+  end
+end