How to access postgres in docker?

We are using the latest container of gitlab in docker, which has the version 8.11.4-ce.0.

We updated our old gitlab version (previous version 8.6.1-ce.0) to 8.11.4-ce.0 with docker rm and docker run method.

After the update process has been finished, it seems go along well, but the data has been gone. (All credentials and repos are not sync with postgres)

We use postgresql(included in the omnibus) and we think the data is not erased, because we persist our data in the /srv/gitlab/data. (As the manual says)

When we access the default postgresql in the docker, we have this message and cannot access our database. How to access to them?

root@cgvapps:/var/opt/gitlab/postgresql/data# psql
psql: could not connect to server: No such file or directory
	Is the server running locally and accepting
	connections on Unix domain socket "/tmp/.s.PGSQL.5432"?

root       254    22  0 07:38 ?        00:00:00 runsv postgresql
root       261   254  0 07:38 ?        00:00:00 svlogd -tt /var/log/gitlab/postgresql
gitlab-+   267   254  0 07:38 ?        00:00:00 /opt/gitlab/embedded/bin/postgres -D /var/opt/gitlab/postgresql/data
gitlab-+   326   267  0 07:38 ?        00:00:00 postgres: checkpointer process   
gitlab-+   327   267  0 07:38 ?        00:00:00 postgres: writer process   
gitlab-+   328   267  0 07:38 ?        00:00:00 postgres: wal writer process   
gitlab-+   329   267  0 07:38 ?        00:00:00 postgres: autovacuum launcher process   
gitlab-+   330   267  0 07:38 ?        00:00:00 postgres: stats collector process   
gitlab-+   338   267  0 07:38 ?        00:00:00 postgres: gitlab gitlabhq_production [local] idle
gitlab-+   339   267  0 07:39 ?        00:00:00 postgres: gitlab gitlabhq_production [local] idle
gitlab-+   508   267  0 07:39 ?        00:00:00 postgres: gitlab gitlabhq_production [local] idle
gitlab-+   516   267  0 07:39 ?        00:00:00 postgres: gitlab gitlabhq_production [local] idle
gitlab-+   523   267  0 07:39 ?        00:00:00 postgres: gitlab gitlabhq_production [local] idle
gitlab-+   830   267  0 07:44 ?        00:00:00 postgres: gitlab gitlabhq_production [local] idle
gitlab-+   831   267  0 07:44 ?        00:00:00 postgres: gitlab gitlabhq_production [local] idle
gitlab-+   850   267  0 07:44 ?        00:00:00 postgres: gitlab gitlabhq_production [local] idle
gitlab-+   861   267  0 07:44 ?        00:00:00 postgres: gitlab gitlabhq_production [local] idle
gitlab-+   862   267  0 07:44 ?        00:00:00 postgres: gitlab gitlabhq_production [local] idle
gitlab-+  1471   267  0 07:48 ?        00:00:00 postgres: gitlab gitlabhq_production [local] idle
gitlab-+  1546   267  0 07:50 ?        00:00:00 postgres: gitlab gitlabhq_production [local] idle
gitlab-+  2364   267  0 07:57 ?        00:00:00 postgres: gitlab gitlabhq_production [local] idle
gitlab-+  2607   267  0 08:01 ?        00:00:00 postgres: gitlab gitlabhq_production [local] idle
gitlab-+  2609   267  0 08:01 ?        00:00:00 postgres: gitlab gitlabhq_production [local] idle