Add ByteString support

Fixes #5.

bower.json

@@ -12,7 +12,8 @@
     "purescript-either": "^2.0.0",
     "purescript-maybe": "^2.0.1",
     "purescript-foldable-traversable": "^2.0.0",
-    "purescript-newtype": "^1.1.0"
+    "purescript-newtype": "^1.1.0",
+    "purescript-bytestrings": "^0.0.3"
   },
   "repository": {
     "type": "git",

src/Database/PostgreSQL.js

@@ -47,3 +47,7 @@ exports._query = function(client) {
         };
     };
 };
+
+exports.unsafeIsBuffer = function(x) {
+    return x instanceof Buffer;
+};

src/Database/PostgreSQL.purs

@@ -22,8 +22,9 @@ module Database.PostgreSQL
 import Control.Monad.Aff (Aff)
 import Control.Monad.Error.Class (catchError, throwError)
 import Control.Monad.Except (runExcept)
+import Data.ByteString (ByteString)
 import Data.Either (Either(..))
-import Data.Foreign (Foreign, readArray, readChar, readString, toForeign)
+import Data.Foreign (Foreign, readArray, readChar, readString, toForeign, unsafeFromForeign)
 import Data.List (List)
 import Data.List as List
 import Data.Maybe (fromJust, Maybe(..))
@@ -134,6 +135,16 @@ instance fromSQLValueArray :: (FromSQLValue a) => FromSQLValue (Array a) where
 instance fromSQLValueList :: (FromSQLValue a) => FromSQLValue (List a) where
     fromSQLValue = map List.fromFoldable <<< traverse fromSQLValue <=< fromRight <<< runExcept <<< readArray
 
+instance toSQLValueByteString :: ToSQLValue ByteString where
+    toSQLValue = toForeign
+
+instance fromSQLValueByteString :: FromSQLValue ByteString where
+    fromSQLValue x
+        | unsafeIsBuffer x = Just $ unsafeFromForeign x
+        | otherwise = Nothing
+
+foreign import unsafeIsBuffer :: ∀ a. a -> Boolean
+
 -- | Create a new connection pool.
 foreign import newPool
     :: ∀ eff