Well, saying that on particular date someone committed patch, wouldn't be really telling. In fact various bits and pieces of underlying logic have been committed for a long time, but now we finally have some functionality visible and available to end users.
This became the case thanks to these two commits, both committed on 20th of February, by Tom Lane.
Implement an API to let foreign-data wrappers actually be functional. This commit provides the core code and documentation needed. A contrib module test case will follow shortly. Shigeru Hanada, Jan Urbanski, Heikki Linnakangas
Add contrib/file_fdw foreign-data wrapper for reading files via COPY. This is both very useful in its own right, and an important test case for the core FDW support. This commit includes a small refactoring of copy.c to expose its option checking code as a separately callable function. The original patch submission duplicated hundreds of lines of that code, which seemed pretty unmaintainable. Shigeru Hanada, reviewed by Itagaki Takahiro and Tom Lane