add community template for Racket

Co-Authored-By: Will Price <willprice94+dev@gmail.com>
Co-Authored-By: Stefan <eu90h@users.noreply.github.com>

community/Racket.gitignore

+# gitignore template for the Racket language
+# website: http://www.racket-lang.org/
+
+# DrRacket autosave files
+*.rkt~
+*.rkt.bak
+\#*.rkt#
+\#*.rkt#*#
+
+# Compiled racket bytecode
+compiled/
+*.zo
+
+# Dependency tracking files
+*.dep
\ No newline at end of file