feat: Add CSAT response APIs (#2503)

Co-authored-by: Pranav Raj S <pranav@chatwoot.com>

app/models/csat_survey_response.rb

@@ -0,0 +1,43 @@
+# == Schema Information
+#
+# Table name: csat_survey_responses
+#
+#  id                :bigint           not null, primary key
+#  feedback_message  :text
+#  rating            :integer          not null
+#  created_at        :datetime         not null
+#  updated_at        :datetime         not null
+#  account_id        :bigint           not null
+#  assigned_agent_id :bigint
+#  contact_id        :bigint           not null
+#  conversation_id   :bigint           not null
+#  message_id        :bigint           not null
+#
+# Indexes
+#
+#  index_csat_survey_responses_on_account_id         (account_id)
+#  index_csat_survey_responses_on_assigned_agent_id  (assigned_agent_id)
+#  index_csat_survey_responses_on_contact_id         (contact_id)
+#  index_csat_survey_responses_on_conversation_id    (conversation_id)
+#  index_csat_survey_responses_on_message_id         (message_id) UNIQUE
+#
+# Foreign Keys
+#
+#  fk_rails_...  (account_id => accounts.id)
+#  fk_rails_...  (assigned_agent_id => users.id)
+#  fk_rails_...  (contact_id => contacts.id)
+#  fk_rails_...  (conversation_id => conversations.id)
+#  fk_rails_...  (message_id => messages.id)
+#
+class CsatSurveyResponse < ApplicationRecord
+  belongs_to :account
+  belongs_to :conversation
+  belongs_to :contact
+  belongs_to :message
+  belongs_to :assigned_agent, class_name: 'User', optional: true
+
+  validates :rating, presence: true, inclusion: { in: [1, 2, 3, 4, 5] }
+  validates :account_id, presence: true
+  validates :contact_id, presence: true
+  validates :conversation_id, presence: true
+end