From PostgreSQL wiki
Governance Charter of the Relationship between the PostgreSQL project and Software in the Public Interest, Inc.
The Core Team of the PostgreSQL project currently consists of the following people: Josh Berkus, Peter Eisentraut, Magnus Hagander, Tom Lane, Bruce Momjian, Dave Page. The Core Team appoints its own members.
The Fundraising Group of the PostgreSQL project initially consists of the members of The PostgreSQL Foundation Inc. at the time of its termination. Thereafter, the Fundraising Group appoints its own members.
The Fundraising Group elects the SPI Project Liason and the SPI Board Observer. These may be the same person. The appointments are subject to the veto of the Core Team. The appointments may be replaced by voting on new representatives at any time. The SPI Board Observer will submit to SPI on an ongoing basis a list of persons eligible for automatic SPI contributing membership in recognition of their contributions to the PostgreSQL project.
Unless specified otherwise, decisions require a majority of votes.