actually support running non-realtime on not-robots

Change-Id: I2d21bc3a43de39d685de550402769f55426b275b
diff --git a/doc/environment_variables b/doc/environment_variables
new file mode 100644
index 0000000..98d51bc
--- /dev/null
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+A list of environment variables useful for running the code on not-robots:
+  AOS_NO_REALTIME
+  AOS_SHM_NAME
+  AOS_TEAM_NUMBER