Generate Session ID on server for synchronized editor

This change allows us to use the session ID immediately for the connection_change and connection_status methods. Hence, we can identify different browser sessions of the same user.

db/migrate/20230912162208_require_session_id_for_event_synchronized_editor.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class RequireSessionIdForEventSynchronizedEditor < ActiveRecord::Migration[7.0]
+  def change
+    change_column_null :events_synchronized_editor, :session_id, false
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.0].define(version: 2023_09_12_142620) do
+ActiveRecord::Schema[7.0].define(version: 2023_09_12_162208) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_trgm"
   enable_extension "pgcrypto"
@@ -166,7 +166,7 @@ ActiveRecord::Schema[7.0].define(version: 2023_09_12_142620) do
     t.jsonb "data"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.uuid "session_id"
+    t.uuid "session_id", null: false
     t.index ["file_id"], name: "index_events_synchronized_editor_on_file_id"
     t.index ["programming_group_id"], name: "index_events_synchronized_editor_on_programming_group_id"
     t.index ["study_group_id"], name: "index_events_synchronized_editor_on_study_group_id"