The ornamental design for a postring, as shown and described.
FIG. 1 is a front perspective view of a post ring, showing my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof, the left and right side elevations being identical images thereof;
FIG. 4 is a top plan view thereof; and,
FIG. 5 is a front perspective view of the post ring, shown in use.
The broken lines showing a post ring in FIG. 5 depicts environmental subject matter that forms no part of the claimed design.
The post ring is shown with symbolic breaks in its lengths. The appearance of any portion of the article between the break lines forms no part of the claimed design.
The dot-dash-dot broken lines in FIGS. 1 and 4 depict the bounds of the post ring and forms no part of the claimed design.