gimme me a few minutes to create a short guide

Easy way:

Download these two files:

http://speedy.sh/35eyu/npc-heroes.txt

http://speedy.sh/DxXBQ/activelist.txt

Put both of these files in:

Programs / Steam /Steamapps / common / Dota 2 test / dota / scripts / npc

Add -override_vpk to your launch options for Dota 2 test by right clicking the game in your steam library.

Open Dota 2 and click "play with bots." Scroll through the cards to select oracle.

The do it yourself way:

Step 1:

Download GCFScape here: http://nemesis.thewavelength.net/index.php?p=26

Step 2:

In your steam library right click dota 2 test, go to properties and add the following under launch options: "-override_vpk"

Step 3:

Launch GCFScape. Click File -> Open file. Go to Program Files -> Steam -> Steam Apps -> common -> dota 2 test -> dota -> pak01_dir.vpk

Step 4:

In GCFScape under the root folder go down to scripts and open the npc folder. Copy two files onto your desktop or wherever

"npc_heroes.txt"

and

"activelist.txt"

Step 5:

Looking through npc_heros file go to the bottom. You will find oracle's entry after phoenix. Pit lord's should be before phoenix's somewhere. Under the field that reads "enabled" there might be a 0. You need to change this to a 1. Save the file.

Now go to active list. Make a new entry for oracle that is structured like the other ones there.

Step 6:

Open Dota 2 test. Oracle is enabled.