Congrats - that is a classic hub seal failure leaking rear end oil. The seal is simple to replace - you just need a 3/8" and 9/16" open end wrenches to pull the axle and a little silicone for the seal flange. Repack the hub bearings w/ grease while you are there - they are oil contaminated. Keep in mind there may be a need to replace the nut the seal rides on/redisleeve if it has a groove where the axle flange seal rides on it. New is $9 or so.
However, the oil may have leaked out contaminating the brake shoes. You need to check the brakes especially if the leak is old/lots of oil got out - as your photo indicates.
What M37dodge said... looks like rear end oil
Something you might want to check also- I had a brake shoe that hung up, or was tight, got the drum hot, which got the hub hot, which got the oil hot, which caused it to leak out a seal that otherwise was ok.
hub leak.
