Nitro/superside: tracker/tracker.go; 3 LoC

Found a possible issue in [Nitro/superside](https://www.github.com/Nitro/superside) at [tracker/tracker.go](https://github.com/Nitro/superside/blob/6fc7b46568ac32458e7ff3de5dba2e33429eff91/tracker/tracker.go#L271-L273)

Below is the message reported by the analyzer for this snippet of code. Beware that the analyzer only reports the first issue it finds, so please do not limit your consideration to the contents of the below message.

> function call at line 272 may store a reference to deploy

[Click here to see the code in its original context.](https://github.com/Nitro/superside/blob/6fc7b46568ac32458e7ff3de5dba2e33429eff91/tracker/tracker.go#L271-L273)

Click here to show the 3 line(s) of Go which triggered the analyzer.

```go
for _, deploy := range times {
t.insertDeployment(&deploy)
}

```

Click here to show extra information the analyzer produced.

```
The following graphviz dot graph describes paths through the callgraph that could lead to a function which writes a pointer argument:
digraph G {
"(insertDeployment, 1)" -> {"(Insert, 1)";}
"(Insert, 1)" -> {}
}

No path was found through the callgraph that could lead to a function which passes a pointer to third-party code.

```

Leave a reaction on this issue to contribute to the project by classifying this instance as a **Bug** :-1:, **Mitigated** :+1:, or **Desirable Behavior** :rocket:
See the descriptions of the classifications [here](https://github.com/github-vet/rangeclosure-findings#how-can-i-help) for more information.

commit ID: 6fc7b46568ac32458e7ff3de5dba2e33429eff91

Start at tracker/tracker.go lines 271-273 and trace insertDeployment through Insert, as shown in the analyzer call graph. Determine whether storing &deploy causes the range-variable pointer problem, then classify the finding as Bug, Mitigated, or Desirable Behavior using the linked classification guidance.

Written by the indexing model from the issue text.