feat: Added Instagram channel migration (#11181)

This PR is part of https://github.com/chatwoot/chatwoot/pull/11054 to
make the review cycle easier.

app/models/account.rb

@@ -56,6 +56,7 @@ class Account < ApplicationRecord
   has_many :data_imports, dependent: :destroy_async
   has_many :email_channels, dependent: :destroy_async, class_name: '::Channel::Email'
   has_many :facebook_pages, dependent: :destroy_async, class_name: '::Channel::FacebookPage'
+  has_many :instagram_channels, dependent: :destroy_async, class_name: '::Channel::Instagram'
   has_many :hooks, dependent: :destroy_async, class_name: 'Integrations::Hook'
   has_many :inboxes, dependent: :destroy_async
   has_many :labels, dependent: :destroy_async

app/models/channel/instagram.rb

@@ -0,0 +1,28 @@
+# == Schema Information
+#
+# Table name: channel_instagram
+#
+#  id           :bigint           not null, primary key
+#  access_token :string           not null
+#  expires_at   :datetime         not null
+#  created_at   :datetime         not null
+#  updated_at   :datetime         not null
+#  account_id   :integer          not null
+#  instagram_id :string           not null
+#
+# Indexes
+#
+#  index_channel_instagram_on_instagram_id  (instagram_id) UNIQUE
+#
+class Channel::Instagram < ApplicationRecord
+  include Channelable
+
+  self.table_name = 'channel_instagram'
+
+  validates :access_token, presence: true
+  validates :instagram_id, uniqueness: true, presence: true
+
+  def name
+    'Instagram'
+  end
+end