Confusing Usage instructions in README

[capnslipp]

The Usage section of the readme tells us to “Integrate pecker into an Xcode scheme to get warnings and errors displayed in the IDE. Just add a new "Run Script Phase" with:” but as far as I know, that's not possible as-written:

• Xcode Targets have Build Phases, with a “New Run Script Phase” menu item.
  
• Xcode Schemes have Pre-actions and Post-actions for the Build action, with a “New Run Script Action” menu item.
  

So this looks like a minor typo but stilll begs the question: What was meant here?

• If an Xcode scheme, change “Run Script Phase”→“Run Script Action”, and it should say whether this should be a pre-action or a post-action.
• If an Xcode target, change “Xcode scheme”→“Xcode target”, and it should say where in the list to order the phase (at the end after Copy Files, at the beginning just after Target Dependencies and Run Build Tool Plug-ins, etc.)