Fix: Add missing SECRET_KEY and ALTCHA_HMAC_KEY to docker.env

Also added a security warning comment to avoid using default credentials in production.

Signed-off-by: Parth Bhatt <paarthbhatt37@gmail.com>

Author: paarthbhatt

docker.env

@@ -1,8 +1,14 @@
+# WARNING: These are default values for local development only.
+# DO NOT use these values in production. Generate proper secret keys.
 POSTGRES_DB=vulnerablecode
+
 POSTGRES_USER=vulnerablecode
 POSTGRES_PASSWORD=vulnerablecode
 
 VULNERABLECODE_DB_HOST=db
 VULNERABLECODE_STATIC_ROOT=/var/vulnerablecode/static/
 
-VULNERABLECODE_REDIS_HOST=vulnerablecode_redis
+VULNERABLECODE_REDIS_HOST=vulnerablecode_redis
+SECRET_KEY=secret
+ALTCHA_HMAC_KEY=0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef
+# ALTCHA_HMAC_KEY must be a 32-byte (64 hex characters) hexadecimal key; override this value in production.