Add a new column before creating rename triggers
Add a new column before creating rename triggers

MySQL doesn't allow us to create a trigger for a column that doesn't
exist yet. Failing with this error:

```
Mysql2::Error: Unknown column 'build_events' in 'NEW': CREATE TRIGGER trigger_6a80c097c862_insert
BEFORE INSERT
ON `services`
FOR EACH ROW
SET NEW.`build_events` = NEW.`job_events`
```

Creating the new column before creating the trigger avoids this.

iiet/iiet-git,axilleas/gitlabhq,dreampet/gitlab,axilleas/gitlabhq,jirutka/gitlabhq,mmkassem/gitlabhq,t-zuehlsdorff/gitlabhq,mmkassem/gitlabhq,stoplightio/gitlabhq,mmkassem/gitlabhq,axilleas/gitlabhq,t-zuehlsdorff/gitlabhq,dplarson/gitlabhq,iiet/iiet-git,dreampet/gitlab,iiet/iiet-git,jirutka/gitlabhq,mmkassem/gitlabhq,dplarson/gitlabhq,dreampet/gitlab,axilleas/gitlabhq,stoplightio/gitlabhq,jirutka/gitlabhq,t-zuehlsdorff/gitlabhq,jirutka/gitlabhq,dplarson/gitlabhq,stoplightio/gitlabhq,stoplightio/gitlabhq,iiet/iiet-git,dplarson/gitlabhq,dreampet/gitlab,t-zuehlsdorff/gitlabhq