Added total time of a course, marking chapters and courses to sync offline.

database/migrations/2022_08_18_094159_create_course_table.php

@@ -16,6 +16,7 @@ return new class extends Migration {
             $table->id();
             $table->integer('course_id')->unique();
             $table->text('name');
+            $table->text('course_duration')->nullable();
             $table->text('thumbnail');
             $table->text('link');
             $table->enum('status', ['unfinished', 'upcoming', 'complete']);