To avoid useless API calls, you need to cache the call results. Before doing that, you must know some things :
The summoner name is not permanent ! A summoner can change his name by purchasing the rename ticket in the store thus, his name will be updated. If you create a sumomner name slug, you must verify periodically if the name is still the same and retrieve the related account information or, let a manual updater button.
For the same reason, you must use the summoner ID as the primary key or you will lost your database/cache relations if the summoner udpate his name (or you will have to update all the relation primary keys, this is not the best idea).
This API requests the Riot servers, which are used by LoL players. So, think about the players : cache your retrieved data to avoid servers flood.
A lot of data can be retrieved with this API, so take a coffee, and think about your database/cache schema.
Now you know everything about this API, you have the opportunity to contribute to this project.