Optimize InitSocialRelay and print more debug msgs

See merge request !80

Add automated building for docker images

See merge request !79

Implement retrying dispatcher requests

See merge request !78

If the first request fails it will retry
after a minute, hour, one day. If it continues
to fail after one day it will mark the server
as not reachable in the database.

As soon as the localhost receives a valid
message again it will mark the server as
reachable and the cycle starts anew

Merge branch '82-mysql-mysqlerror-error-1064-you-have-an-error-in-your-sql-syntax-check-the-manual-that-corresponds-to-your-mysql' into 'master'

Resolve "*mysql.MySQLError: Error 1064: You have an error in your SQL syntax; check the manual that corresponds to your MySQL..."

Closes #82

See merge request !77

Resolve "*mysql.MySQLError: Error 1064: You have an error in your SQL syntax; check the manual that corresponds to your MySQL..."

Resolve "Add notification to ganggo"

Closes #18

See merge request !76

Resolve "Updater will not kill old process properly"

Closes #81

See merge request !75

Sentry logging

Closes #69

See merge request !73

closes #69

closes #68

related to 38585a06

AP improvements

See merge request !72

by using artifacts instead of caching. It seams like caching
is kind of broken or I misunderstand how its used correctly.

i18n: Update Polish translation

See merge request !71

Signed-off-by: Marcin Mikołajczak <me@m4sk.in>

Implement ActivityPub

See merge request ganggo/ganggo!55

Add and use bintray fetcher in updater agent

See merge request !70

fixes skipping public assets directory