Foreign Keys in eloquent migrations

When writing your migrations in Eloquent you may want to define something like 

 $table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');

To do this (in version 6 of Laravel) you must define the foreign keys using the following syntax to match the new bigIncrements autoincrement key added by Laravel to all tables.

$table->unsignedBigInteger('user_id');