add model dir

Author: yinhaofeng

doc/source/index.rst

@@ -41,6 +41,14 @@
    paddlerec/yaml.md
    paddlerec/benchmark.md
 
+.. toctree::
+   :maxdepth: 1
+   :numbered:
+   :caption: 模型介绍
+   :name: Model introduction
+
+   paddlerec/model_introduce.md
+   
 .. toctree::
    :maxdepth: 1
    :numbered:

doc/source/paddlerec/model_introduce.md

@@ -0,0 +1,26 @@
+## [内容理解模型库](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/contentunderstanding)
+### [tagspace文本分类模型](https://github.com/PaddlePaddle/PaddleRec/tree/master/models/contentunderstanding/tagspace)
+### [textcnn文本分类模型](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/contentunderstanding/textcnn)
+
+## [匹配模型库](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/match)
+### [DSSM文本匹配模型](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/match/dssm)
+### [match-pyramid文本匹配模型](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/match/match-pyramid)
+### [multiview-simnet文本匹配模型](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/match/multiview-simnet)
+
+## [召回模型库](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/recall)
+### [word2vec模型](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/recall/word2vec)
+
+## [排序模型库](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/rank)
+### [dnn模型](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/rank/dnn)
+### [FM模型](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/rank/fm)
+### [deepfm模型](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/rank/deepfm)
+### [logistic_regression模型](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/rank/logistic_regression)
+### [wide&deep模型](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/rank/wide_deep)
+### [gatednn模型](https://github.com/PaddlePaddle/PaddleRec/tree/master/models/rank/gateDnn)
+### [naml模型](https://github.com/PaddlePaddle/PaddleRec/tree/master/models/rank/naml)
+
+## [多任务学习模型库](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/multitask)
+### [MMOE模型](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/multitask/mmoe)
+### [ESMM模型](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/multitask/esmm)
+
+## [重排序模型库](https://github.com/PaddlePaddle/PaddleRec/blob/master/models/rerank)