Exit explicitly when running un-spring rails commands

Prevents "warning: already initialized constant APP_PATH" and
potentially other code from running that you don't expect to run.

Fixes #259.

Author: jonleighton

CHANGELOG.md

@@ -3,6 +3,9 @@
 * Detect old binstubs generated with Spring 1.0 and exit with an error.
   This prevents a situation where you can get stuck in an infinite loop
   of spring invocations.
+* Avoid `warning: already initialized constant APP_PATH` when running
+  rails commands that do not use spring (e.g. `bin/rails server` would
+  emit this when you ^C to exit)
 
 ## 1.1.1
 

lib/spring/client/rails.rb

@@ -25,6 +25,7 @@ def call
           require "spring/configuration"
           ARGV.shift
           load Dir.glob(Spring.application_root_path.join("{bin,script}/rails")).first
+          exit
         end
       end
     end