Gracefull exit on sigTERM

Like the sigINT that was already handled, postgrest
should gracefuly shut down on a sigTERM. This is a
common way of stopping processes, used amongst
others by docker.

See: https://stackoverflow.com/questions/4042201/how-does-sigint-relate-to-the-other-termination-signals

CHANGELOG.md

@@ -6,6 +6,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 ## Unreleased
 
 ### Fixed
+- Terminate gracefully on SIGTERM - @recmo
 
 ## [0.3.1.0] - 2016-02-28
 

src/PostgREST/Main.hs

@@ -60,10 +60,11 @@ main = do
 
 #ifndef mingw32_HOST_OS
   tid <- myThreadId
-  void $ installHandler keyboardSignal (Catch $ do
+  forM_ [sigINT, sigTERM] $ \sig ->
-      P.release pool
+    void $ installHandler sig (Catch $ do
-      throwTo tid UserInterrupt
+        P.release pool
-    ) Nothing
+        throwTo tid UserInterrupt
+      ) Nothing
 #endif
 
   result <- P.use pool $ do