Whenever we want to expose data to Views, we need to define this data in a way Views can understand it. That is actually what EntityViewsData::getViewsData() does for content entities. However, since we are dealing with something custom, we can do so by implementing hook_views_data(). A lot can go into it, but we'll start things simple.
Let's implement this hook and simply describe our first table (that of the players) and only one field, namely, the player ID, to start with.
In Views lingo, the term field does not have to relate necessarily to entity fields or anything like that, but rather to an individual piece of data from a data source (real or not). A typical example to consider is a column in a table, but it can also be ...
