The ornamental design for a skateboardrack, as shown and described.
FIG. 1 is a front perspective view of a skateboard rack showing inventors' new design;
FIG. 2 is a rear perspective view of the skateboard rack invention;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a front elevational view thereof;
FIG. 7 is a top plan view thereof;
FIG. 8 is a bottom plan view thereof; and,
FIG. 9 is a rear perspective view of the skateboard rack invention with broken lines showing possible attachments thereon.
The broken line showing of attachments to the skateboard rack is included for the purpose of illustrating environmental matter and forms no part of the claimed design.