Logger hash message

[jodosha]

This proposal introduces a small change in the logger. When we pass a Hash, it should print all the key/value pairs instead of wrapping them into :message key.

Default logger

Before

logger.info(http: "HTTP/1.1", verb: "GET")

  # => [bookshelf] [INFO] [2017-01-31 14:40:13 +0100] {:http=>"HTTP/1.1", :verb=>"GET"}

After

logger.info(http: "HTTP/1.1", verb: "GET")

  # => [bookshelf] [INFO] [2017-01-31 14:40:51 +0100] HTTP/1.1 GET

JSON logger

Before

logger.info(http: "HTTP/1.1", verb: "GET")

  # => {"app":"bookshelf","severity":"INFO","time":"2017-01-31T13:36:18Z","message":{"http":"HTTP/1.1","verb":"GET"}}

After

logger.info(http: "HTTP/1.1", verb: "GET")

  # => {"app":"bookshelf","severity":"INFO","time":"2017-01-31T13:41:44Z","http":"HTTP/1.1","verb":"GET"}

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/cc @AlfonsoUceda @hanami/issues @hanami/ecosystem for review 👍

[AlfonsoUceda]

LGTM @jodosha 👍