allowExpressions configuration option not documented

[govindrai]

After you follow the directions to setup the debugger, you get into the UI and then realize you can't use snapshots or logpoints because:

None of the examples show the allowExpressions configuration option and the documentation doesn't call it out/explain the option anywhere (at least I was not able to find this on the github repo nor the official google cloud debugger docs).

Please document it, otherwise you have to redeploy the app again.

[mctavish]

Valid feedback. The documentation should be updated to both include the allowExpressions option in the examples. It should probably also be included in the samples in this repo.