[REQUEST] Add an error handler to the Mongoose sample injector

[magnus195]

Is your feature request related to a problem? Please describe.
I had some problems writing a decent error handler and got errors from it (not the good ones).

Describe the solution you would like
I never figured out how to make it work in a good way so I'm hoping someone can look at it if my PR get's merged.
This can be considered low priority

Additional context
This issue is related to #9

[Twaha-Rahman]

An error handler was added with #32.