update readme

README.markdown

@@ -60,15 +60,15 @@ These options control all modes of foreman's operation.
 
 Start one instance of each process type, interleave the output on stdout:
 
-    $ `foreman start`
+    `$ foreman start`
 
 Export the application in upstart format:
 
-    $ `foreman export upstart /etc/init`
+    `$ foreman export upstart /etc/init`
 
 Run one process type from the application defined in a specific Procfile:
 
-    $ `foreman start alpha -p ~/app/Procfile`
+    `$ foreman start alpha -p ~/app/Procfile`
 
 ## COPYRIGHT