Implement offline POST method for starting an offline participation

app/models/offline.rb

@@ -4,6 +4,7 @@
 #
 #  id         :integer          not null, primary key
 #  end_time   :datetime
+#  name       :string           not null
 #  start_time :datetime         not null
 #  created_at :datetime         not null
 #  updated_at :datetime         not null
@@ -23,5 +24,17 @@ class Offline < ApplicationRecord
   has_one_attached :start_image
   has_one_attached :end_image
 
+  validates :name, presence: true
   validates :start_time, presence: true
+
+  validate :start_image_is_present
+
+  def start_image_is_present
+    logger = Logger.new(STDOUT)
+    logger.info "TESTddfzefzef"
+    logger.info self.start_image.attached?
+    if !self.start_image.attached?
+      errors.add(:start_image, I18n.t("activerecord.errors.models.offline.attributes.start_image.blank"))
+    end
+  end
 end