Add OpenBSD compatibility for spring status

- ps -A is an alias for ps -ax, which works across linux
  and BSD platforms
- ps -ax -o args= -- args is an alias for command which
  works across linux and BSD platforms

Author: Matthias Geier

CHANGELOG.md

@@ -1,3 +1,7 @@
+## Next version
+
+* Add OpenBSD compatibility for `spring status`. Issue #299.
+
 ## 1.2.0
 
 * Accept -e and --environment options for `rails console`.

lib/spring/client/status.rb

@@ -17,11 +17,11 @@ def call
       end
 
       def print_process(pid)
-        puts `ps -p #{pid} -o pid= -o args=`
+        puts `ps -p #{pid} -o pid= -o command=`
       end
 
       def application_pids
-        candidates = `ps -A -o ppid= -o pid=`.lines
+        candidates = `ps -ax -o ppid= -o pid=`.lines
         candidates.select { |l| l =~ /^(\s+)?#{env.pid} / }
                   .map    { |l| l.split(" ").last   }
       end