fix mailgun import and empty object check

Merge pull request #7 from wildsurfer/master

Merge pull request #33 from PierreBrisorgueil/patch-1

fix notifications in config

Merge pull request #27 from pengfei-xue/master

update document

add notify type dingding

Merge pull request #20 from daya0576/patch-1

Update Config.md

Merge pull request #14 from floriancourgey/patch-4

Merge pull request #18 from cmpz-engineering/master

Add Pagerduty Notification client

Update notify.go - english (2)

Merge pull request #8 from damarte/master

Update requests.go