Postgres concat all

I need connect all columns (unknown columns) from every rows to one string

I want do sth like this:

select concat(*) from table;

The problem is that the function concat doesn't take parameter "*"

Anyone can help me?

Example:

Table

GID | Name
----------
1   | nameA
2   | nameB
3   | nameC

I need on output:

1nameA
2nameB
3nameC