Case for issues on GitHub Webhooks

Store to database or throw error on DB connect failure or failure to
execute query.
Use webhook->parsed->issue instead of issue for issues case
Repository info not stored at issues level

Use $webhook->parsed->repository->* instead of
$webhook->parsed->issue->repository->*
Add UPDATE portion of query for existing columns

Still need to add new columns to table, but for now update what I have
Insert & update into missing useful columns

Added Updated_At & Assignee
Resolve issue #33

Add missing columns to issues table, append to INSERT, and add to UPDATE
Merge pull request #34 from shgysk8zer0/isue_33

Merge branch Isue 33