shovel: save static data to integration table

[ryandotsmith]

Let's say I have two events that are related to the same contract and the events both have the same type of data. For example: AddKey(address,bytes32[2]) and RemoveKey(address,bytes32[2]). It would be nice to save both of these events to the same pg table and for that table to have a column named "kind" where I can set values like "add" or "remove". Or possible I may want to set the event name on the table.

...
"event": {
  "name": "AddKey",
  "inputs": [
    {"name": "addr", "type": "address", "column": "addr"},
    {"name": "keys", "type": "bytes32[2]", "column": "key"}
  ],
  "extra": [
    {"name": "AddKey", "type": "text", "column": "kind"}
  ]
}