added racetrack-oval-v0 and train script (#652)

Co-authored-by: Christoph Luther <christophluther@eduroam-078-104-029-238.wlan.univie.ac.at>

Author: christophluther

.DS_Store

@@ -145,3 +145,5 @@ jupyter_execute
 
 # IDE
 .idea
+
+racetrack_oval_ppo/

.gitignore

@@ -101,6 +101,10 @@ def _register_highway_envs():
         id="racetrack-large-v0",
         entry_point="highway_env.envs.racetrack_env:RacetrackEnvLarge",
     )
+    register(
+        id="racetrack-oval-v0",
+        entry_point="highway_env.envs.racetrack_env:RacetrackEnvOval",
+    )
 
     # roundabout_env.py
     register(