Implement `file_replace_content' task action

lib/producer/core/actions/file_replace_content.rb

@@ -0,0 +1,27 @@
+module Producer
+  module Core
+    module Actions
+      class FileReplaceContent < Action
+        def apply
+          fs.file_write path, replaced_content
+        end
+
+        def path
+          arguments[0]
+        end
+
+        def pattern
+          arguments[1]
+        end
+
+        def replacement
+          arguments[2]
+        end
+
+        def replaced_content
+          fs.file_read(path).gsub pattern, replacement
+        end
+      end
+    end
+  end
+end