The ornamental design for a gatewaycontroller, as shown and described.
FIG. 1 is a perspective view of a first embodiment of a gateway controller;
FIG. 2 is a front elevation view of the gateway controller of FIG. 1;
FIG. 3 is a left side view of the gateway controller of FIG. 1;
FIG. 4 is a right side view of the gateway controller of FIG. 1;
FIG. 5 is a top plan view of the gateway controller of FIG. 1;
FIG. 6 is a bottom plan view of the gateway controller of FIG. 1;
FIG. 7 is a perspective view of a second embodiment of a gateway controller; and,
FIG. 8 is a front elevation view of the gateway controller of FIG. 7.
The broken lines in the figures are included for the purpose of illustrating portions of the gateway controller that form no part of the claimed design.