Rails and jsonb type “jsonb” does not exist

Question

After looking around I discovered that my postgresql version is not 9.4 by running the right command

postgres=# SHOW SERVER_VERSION;
server_version 
----------------
9.1

So I had simply to upgrade my postgresql to 9.4.

By the way I followed this article to do the upgrading which I found very handy.

Now :

postgres=# SHOW SERVER_VERSION;
 server_version 
----------------
 9.4.1

Hope this help someone in the same situation.