pgloader fails to migrate mysql database in postgresql from synlology gitlab to gitlab-ce

We wanted to migrate gitlab from a docker-version in synology v. 9.4.4 to gitlab-ce omnibus. Originally we used Maria-DB. Now it looks like I have to use Postgresql.

I used the following instructions https://docs.gitlab.com/ce/update/mysql_to_postgresql.html until the usage of pgloader: sudo -u gitlab-psql pgloader commands.load

This is my output:

sudo -u gitlab-psql pgloader commands.load
2018-10-17T09:42:11.092000Z LOG Migrating from #<MYSQL-CONNECTION mysql://git@localhost:3306/gitlabhq_production {100ABDC783}>
2018-10-17T09:42:11.095000Z LOG Migrating into #<PGSQL-CONNECTION pgsql://gitlab-psql@unix://var/opt/gitlab/postgresql:5432/gitlabhq_production {100ABDE073}>
2018-10-17T09:42:13.647000Z WARNING Source column "public"."abuse_reports"."id" is casted to type "bigserial" which is not the same as "integer", the type of current target database column "public"."abuse_reports"."id".
2018-10-17T09:42:13.647000Z WARNING Source column "public"."abuse_reports"."reporter_id" is casted to type "bigint" which is not the same as "integer", the type of current target database column "public"."abuse_reports"."reporter_id".
2018-10-17T09:42:13.648000Z WARNING Source column "public"."abuse_reports"."user_id" is casted to type "bigint" which is not the same as "integer", the type of current target database column "public"."abuse_reports"."user_id".
2018-10-17T09:42:13.648000Z WARNING Source column "public"."abuse_reports"."created_at" is casted to type "timestamptz" which is not the same as "timestamp without time zone", the type of current target database column "public"."abuse_reports"."created_at".
2018-10-17T09:42:13.648000Z WARNING Source column "public"."abuse_reports"."updated_at" is casted to type "timestamptz" which is not the same as "timestamp without time zone", the type of current target database column "public"."abuse_reports"."updated_at".
KABOOM!
FATAL error: pgloader failed to find column "public"."abuse_reports"."cached_markdown_version" in target table "\"public\".\"abuse_reports\""
An unhandled error condition has been signalled:
   pgloader failed to find column "public"."abuse_reports"."cached_markdown_version" in target table "\"public\".\"abuse_reports\""




What I am doing here?

pgloader failed to find column "public"."abuse_reports"."cached_markdown_version" in target table "\"public\".\"abuse_reports\""

pgloader is in version 3.5.2

I had to import my gitlab-backup db-dump to a new Mysql database in version 5.7 on Ubuntu 16.04 Postgresql is the embedded version.

I compared the table schemas and it lookes like in the mysql-version there are more columns then in the created schema from postgresql.

The column above abuse_reports.cached_markdown_version is in Mysql but not in Postgresql. I started to delete columns in Mysql. But then in application_settings there was a whole bunch of columns too much. pgdump aborts always because postgresql schema has less columns then mysql has. How can that happen? Same version of gitlab but totaly different schemas?