Add ability to specify toxics in the config file

[seanhoughton]

I would like to declaratively define the toxics configuration in the config file. However, the toxics section is explicitly excluded from deserialization here: https://github.com/Shopify/toxiproxy/blob/master/proxy.go#L32

I tried to follow the history of this code to see if I could understand why this wouldn't be allowed but could find anything.

Without this option you need an init container that waits for the service to be up and then runs a bunch of curl commands which is a lot more complicated and fiddly than just having a single JSON file which defines the state of the proxy.

Thanks for the tool!

PS - this is related to someone's question about documenting the config format. Although an example was added, the issue of toxics in the config which were assumed by the author of the issue was never resolved. #163

[KernelDeimos]

I found this PR when I looked for an example of adding toxics in the config file. Well, that sure didn't work, nor was there any error message even though my additional configuration wasn't being interpreted. (well that part makes sense... #golangproblems eh?)