Refactor: rename module and class names.

* Module: Graph -> Network
* Class: JsonBuilder -> Graph

app/models/network/commit.rb

@@ -0,0 +1,39 @@
+require "grit"
+
+module Network
+  class Commit
+    include ActionView::Helpers::TagHelper
+
+    attr_accessor :time, :spaces, :refs, :parent_spaces
+
+    def initialize(commit)
+      @_commit = commit
+      @time = -1
+      @spaces = []
+      @parent_spaces = []
+    end
+
+    def method_missing(m, *args, &block)
+      @_commit.send(m, *args, &block)
+    end
+
+    def add_refs(ref_cache, repo)
+      if ref_cache.empty?
+        repo.refs.each do |ref|
+          ref_cache[ref.commit.id] ||= []
+          ref_cache[ref.commit.id] << ref
+        end
+      end
+      @refs = ref_cache[@_commit.id] if ref_cache.include?(@_commit.id)
+      @refs ||= []
+    end
+
+    def space
+      if @spaces.size > 0
+        @spaces.first
+      else
+        0
+      end
+    end
+  end
+end