Doc indexing (#633)

* initail commit

* stash

* rename outline file and add indexing sections

* add sections

* add outline sections

* fixed wikipedia dataset hyperlink

* data.rst

* Revert "data.rst"

This reverts commit d0d08c5.

* index.rst

* edit based on code review

* fix section level

* remove TOC and add outline ind index.rst

* stash

* remove hyperlinks to files outside docs

* add a word spelling

Author: hepengfe

docs/index.rst

@@ -2,17 +2,23 @@ Welcome to Forte's documentation!
 ******************************************
 
 .. toctree::
-   :maxdepth: 1
+   :maxdepth: 2
+   
+   outline.md
+
+
+.. toctree::
+   :maxdepth: 2
 
-   get_started.md
+   tutorial/get_started.md
 
 .. toctree::
    :maxdepth: 2
 
-   examples.md
-   ontology_generation.md
-   audio_processing.md
-   data_pack.md
+   tutorial/examples.md
+   tutorial/ontology_generation.md
+   tutorial/audio_processing.md
+   tutorial/data_pack.md
 
 API
 ====

docs/outline.md

@@ -0,0 +1,39 @@
+This outline is currently **in progress** so many sections are empty.
+
+# Outline
+## 0. Overview
+* [get started](tutorial/get_started.md)
+## 1. Handling Structured Text Data
+* [data_pack](tutorial/data_pack.md)
+## 2. Processing Raw Text
+### Reader
+### Ontology
+### Dataset
+* wikipedia dataset
+### Serialization
+## 3. Building a NLP Pipeline
+### Text Classification
+* use text classification as a example to introduce pipeline components 
+## 4. Linguistic Analysis
+* Analyze linguistic structure within a sentence.
+* more concrete examples of `context` and `get_data()` on top of [Handling Structured Text Data](#1-handling-structured-text-data)
+### Part-of-Speech Tagging
+## 5. Language Modeling with External Library
+* predictor
+## 6. Application
+### Information Extraction
+#### Named Entity Recognition
+#### Relation Extraction
+### Information Retrieval
+#### Indexing
+#### Ranking
+### Machine Translation
+### Text Generation
+### Question Answering System
+### Chatbot
+## 7. Tasks on Other Modalities
+### Audio
+#### Automatic Speech Recognition
+#### Speaker Segmentation
+### Image Data
+#### Image Classification

docs/spelling_wordlist.txt

@@ -139,4 +139,5 @@ docstrings
 numpy
 jsonpickle
 crowdworkers
-subword
+subword
+wikipedia