It was working incorrectly since my last PR. Sorry.
Note that may seem useful to show them all, but it ends up being a
never-ending task that annoys the user.
On the other hand, I made two public functions to improve the
readability of the controller code.
Following the discussion in #304, I tried this solution using the
strict mode of mariadb/mysql.
Split the Clusters and People queries to minimize the considerations
of both functions. Otherwise I had to add many nested ifs.
Also change to only show 15 clusters (as a small optimization) since
there is no point in showing everything, and it is better to show these
little by little.
Matias De lellis