The ornamental design for a compostbucket, as shown and described.
FIG. 1 is an exploded perspective view of a compost bucket, showing my new design;
FIG. 2 is a perspective view of the compost bucket, once it has been assembled, showing my new design;
FIG. 3 is a front elevational view of the compost bucket thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left side elevational view thereof
FIG. 6 is a right side elevational view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The broken lines showing of holes in the lid, and the bottom surface of the bucket, are for the purpose of illustrating portions of the compost bucket that form no part of the claimed design.