Postgres Example (#490)

* creating postgres example - fixes #489

* postgres example glide fix

* all the changes

* use fn call

* removing func.yaml

* removing build.sh

* test.sh cleanup

examples/postgres/glide.yaml

@@ -0,0 +1,4 @@
+package: github.com/iron-io/functions/examples/postgres
+import:
+- package: github.com/lib/pq
+- package: github.com/pkg/errors