text: create table if not exists functions(
      id serial primary key not null,
      name varchar (100) not null,
      module_id int not null,
      created_at timestamp not null,
      updated_at timestamp not null,
      deleted_at timestamp
  );
  
  create index index_function_module_id on functions (module_id);
  create index index_function_name on functions (name);
  
  comment on column functions.id is 'id';
  comment on column functions.module_id is 'module id';
  comment on column functions.name is 'function name';
  comment on column functions.created_at is 'Save timestamp when create';
  comment on column functions.updated_at is 'Save timestamp when update';
  comment on column functions.deleted_at is 'Timestamp delete logic this record. When delete save current time';
  
  alter table functions add constraint function_module_id foreign key (module_id) references modules (id);
  