Provide proper JSON details for errors

Refines HTTP codes for server vs client problems

Fixes #92
Fixes #40

test/Feature/AuthSpec.hs

@@ -14,7 +14,7 @@ spec :: Spec
 spec = before resetDb $ around withApp $
   describe "authorization" $ do
     it "hides tables that anonymous does not own" $
-      get "/authors_only" `shouldRespondWith` 400 -- TODO: should be 404
+      get "/authors_only" `shouldRespondWith` 404
     it "indicates login failure" $ do
       let auth = authHeader "postgrest_test_author" "fakefake"
       request methodGet "/authors_only" [auth] ""

test/Feature/InsertSpec.hs

@@ -73,7 +73,7 @@ spec = before resetDb $ around withApp $ do
       it "fails with 400 and error" $
         post "/simple_pk" "}{ x = 2"
           `shouldRespondWith` ResponseMatcher {
-            matchBody    = Just [json| {"error":"Failed to parse JSON payload. Failed reading: satisfy"} |]
+            matchBody    = Just [json| {"message":"Failed to parse JSON payload. Failed reading: satisfy"} |]
           , matchStatus  = 400
           , matchHeaders = []
           }