Create and run migration to drop sessions table

Our app is using the cookie_store https://github.com/portagenetwork/roadmap/blob/deployment-portage/config/initializers/session_store.rb. As a result, the sessions table is no longer needed.

db/migrate/20240820190548_drop_sessions_table.rb

@@ -0,0 +1,11 @@
+class DropSessionsTable < ActiveRecord::Migration[6.1]
+  def up
+    drop_table :sessions
+  end
+
+  def down
+    # rollback will the execute the initial migration code written to create the sessions table
+    require Rails.root.join('db/migrate/20181024120747_add_sessions_table.rb')
+    AddSessionsTable.new.change
+  end
+end