Add database connection pool details to Process state

[bensheldon]

It might be helpful to provide a snapshot of the database connection pool settings and usage to the Process state.

For the database used by GoodJob (e.g. take it off the GoodJob::Process connection):

• Size of the database connection pool
• Number of active connections being used right now

[dixpac]

@bensheldon did I understand this correctly:

You want to this information insideGoodJob::Process#current_state

Something like this:

    def self.ns_current_state
      {
        ...
        db_conection_pool_size: connection_pool.size,
        db_connection_pool_busy: connection_pool.connections.count(&:in_use?)
      }
    end

For the "Size of the database connection pool" do you want

• connection_pool.size - Total capacity of the connection pool
• connection_pool.connections.size - Total number of opened connections (idle or in_use)

[bensheldon]

@dixpac that looks perfect!

One naming request: what do you think of "active" instead of "busy"?

[dixpac]

Awesome!
I'll submit PR then

Agree about the naming 🤘🏽