docker运行偶尔就会panic

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**Gorse version**
Print build info by the `--version` option.

**Describe the bug**
panic: runtime error: index out of range [33578] with length 1281

goroutine 63 [running]:
github.com/zhenghaoz/gorse/base.(*MapIndex).ToName(0xc0039ff8c0?, 0x1e165b0?)
/go/gorse/base/index.go:135 +0x3d
github.com/zhenghaoz/gorse/worker.(*Worker).collaborativeRecommendHNSW(0xc0002a02c0, 0xc00c382850?, {0xc00c382850, 0xa}, {0x3095650, 0x0, 0x0}, 0xc00c3efb80, 0xc00c279160)
/go/gorse/worker/worker.go:884 +0x528
github.com/zhenghaoz/gorse/worker.(*Worker).Recommend.func2(0x0?, 0x0)
/go/gorse/worker/worker.go:593 +0xcaf
github.com/zhenghaoz/gorse/base/parallel.Parallel(0x7, 0xc00c5cbf40?, 0xc0001e6460)
/go/gorse/base/parallel/parallel.go:39 +0xf7
github.com/zhenghaoz/gorse/worker.(*Worker).Recommend(0xc0002a02c0, {0xc002d68a00, 0x7, 0x8})
/go/gorse/worker/worker.go:546 +0x1074
github.com/zhenghaoz/gorse/worker.(*Worker).Serve.func1()
/go/gorse/worker/worker.go:405 +0x425
github.com/zhenghaoz/gorse/worker.(*Worker).Serve(0xc0002a02c0)
/go/gorse/worker/worker.go:417 +0xdbf
main.glob..func1.1()
/go/gorse/cmd/gorse-in-one/main.go:109 +0x3f
created by main.glob..func1
/go/gorse/cmd/gorse-in-one/main.go:107 +0x9f1

**To Reproduce**
Steps to reproduce the behavior.

**Expected behavior**
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**Additional context**
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