I worked with PostgreSQL since the 6.5 release. I first contributed by translating the 7.4 PostgreSQL manual, and its command-line tools, into French. This effort still goes on. Right now, manuals from 7.4 to 10 are available in French. The work on the v11 manual will begin in may. I also contributed with code. My main work remains for pgAdmin (translations, bugfixes, and new features), but I also added some functionalities in various releases of PostgreSQL. I also wrote some patches for phpPgAdmin, pgPool, pgpoolAdmin, check_postgres.pl, etc. I try to participate as much as possible in the events organized by the community (mostly FOSDEM/PGday, and PGConf.eu 2010 till 2017) to either help in the organization or give a talk, and by other free communities. Finally, I try to communicate about PostgreSQL, usually by writing articles in a french Linux magazine, and a book (2nd edition released on december last year).
I have been on the PostgreSQL Europe board for 7 years now, as the treasurer of the NPO. I'm in touch with the bank account manager, the accountants, and the french authorities (mostly the tax agency). We make sure everything is done by the law. It takes quite some time, but it helps a lot to make sure we can organize great events for the community.