Stop adding duplicates to workspace

lib/cocoapods/installer.rb

@@ -105,7 +105,8 @@ module Pod
       pods_projpath = File.join(config.project_pods_root, 'Pods.xcodeproj')
       root = Pathname.new(root).expand_path
       [projpath, pods_projpath].each do |path|
-        workspace << Pathname.new(path).expand_path.relative_path_from(root)
+        path = Pathname.new(path).expand_path.relative_path_from(root).to_s
+        workspace << path unless workspace.include? path
       end
       workspace.save_as(xcworkspace)
 

lib/cocoapods/xcode/workspace.rb

@@ -30,6 +30,10 @@ module Pod
         @projpaths << projpath
       end
       
+      def include?(projpath)
+        @projpaths.include?(projpath)
+      end
+      
       TEMPLATE = %q[<?xml version="1.0" encoding="UTF-8"?><Workspace version="1.0"></Workspace>]
       def to_s
         doc = NSXMLDocument.alloc.initWithXMLString(TEMPLATE, options:0, error:nil)