added backend for pgTap (#51)

Co-authored-by: tudor <[email protected]>

Author: tdrz

.gitmodules

@@ -4,3 +4,6 @@
 [submodule "pglite/pgvector"]
 	path = pglite/vector
 	url = https://github.com/pgvector/pgvector.git
+[submodule "pglite/pgtap"]
+	path = pglite/pgtap
+	url = https://github.com/theory/pgtap.git

pglite/Makefile

@@ -5,7 +5,8 @@ include $(top_builddir)/src/Makefile.global
 
 SUBDIRS = \
 		pg_ivm \
-		vector
+		vector \
+		pgtap
 
 prefix ?= /install/pglite
 EXTENSIONS_BUILD_ROOT := /tmp/extensions/build