Querying `/node/stats?format=json` does not properly serialize the node stats

[ctrowat]

When making a GET request to the specified endpoint node stats are not returned correctly. Instead I get a response like this:

{
    "DEVICE1": "#<Oxidized::Node::Stats:0x000055fbadc63230>",
    "DEVICE2": "#<Oxidized::Node::Stats:0x000055fbadc31168>",
    "DEVICE3": "#<Oxidized::Node::Stats:0x000055fbadb44110>",
    "DEVICE4": "#<Oxidized::Node::Stats:0x000055fbadc2a750>",
...
}

[fernandolcx]

same here