Merge pull request #152 from takeda/psycopg2

Add openssl for psycopg2-binary on Darwin

overrides.nix

@@ -475,6 +475,8 @@ self: super:
 
   psycopg2-binary = super.psycopg2-binary.overridePythonAttrs (
     old: {
+      buildInputs = old.buildInputs
+        ++ lib.optional stdenv.isDarwin pkgs.openssl;
       nativeBuildInputs = old.nativeBuildInputs ++ [ pkgs.postgresql ];
     }
   );