Added api details in readme (#109)

* v2.7.7

* updated api details

README.md

@@ -14,12 +14,11 @@ The intent is to simplify the request process by handling the tedious logic. It'
 
 * [Installation](#installation)
 * [Usage](#usage)
+* [API Details](#api-details)
 * [Examples](#examples)
 * [Starter Guide](#starter-guide)
 * [Test](#test)
 * [Issues](#issues)
-* [Contribution](#contribution)
-* [LICENSE](#license)
 
 
 ## 🚚 Installation
@@ -46,6 +45,38 @@ let ebay = new eBay({
 
 Check out the [Starter Guide](https://pajaydev.github.io/ebay-node-api) documentation with examples to get started.
 
+## API details
+
+### Without Auth flow
+
+HTTP Method | Methods           | Description |   Usage | Offical doc
+----------- | ------------------ | ----------- | ---------------- | --------------------------------
+GET         | findItemsByKeywords       | Searches for items on eBay by a keyword query.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/finding.js#L21) | [doc](https://developer.ebay.com/devzone/finding/callref/finditemsbykeywords.html)
+GET         | findCompletedItems       | Searches for items whose listings are completed and are no longer available for sale by category (using categoryId), by keywords (using keywords), or a combination of the two.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/finding.js#L40) | [doc](https://developer.ebay.com/devzone/finding/callref/findCompletedItems.html)
+GET         | findItemsByProduct       | Searches for items on eBay using specific eBay product values.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/finding.js#L55) | [doc](https://developer.ebay.com/devzone/finding/callref/finditemsbykeywords.html)
+GET         | findItemsAdvanced       | Searches items on eBay by category or keyword or both.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/finding.js#L65) | [doc](https://developer.ebay.com/devzone/finding/callref/findItemsAdvanced.html)
+GET         | getSingleItem       | Retrieves publicly visible details about one listing on eBay.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/finding.js#L40) | [doc](https://developer.ebay.com/Devzone/shopping/docs/CallRef/GetSingleItem.html)
+GET         | getMultipleItems       | Retrieves publicly available data for one or more listings.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/shopping.js#L49) | [doc](https://developer.ebay.com/Devzone/shopping/docs/CallRef/GetMultipleItems.html)
+GET         | getShippingCosts       | Retrieve estimated shipping cost to ship an active item to a specified destination country and postal code.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/finding.js#L40) | [doc]( https://developer.ebay.com/devzone/shopping/docs/callref/GetShippingCosts.html)
+GET         | getItemStatus       | Get item status for given item ids.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/shopping.js#L28) | [doc](https://developer.ebay.com/Devzone/shopping/docs/CallRef/GetItemStatus.html)
+GET         | getUserDetails       | Get User Profile.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/shopping.js#L19) | [doc](https://developer.ebay.com/Devzone/shopping/docs/CallRef/GetUserProfile.html)
+
+
+### With Auth flow
+
+HTTP Method | Methods           | Description |   Usage | Offical doc
+----------- | ------------------ | ----------- | ---------------- | --------------------------------
+GET         | searchItems       | Searches for eBay items by various query parameters and retrieves summaries of the items. You can search by keyword, category, eBay product ID (ePID), or GTIN, charity ID, or a combination of these.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/searchApi.js#L17) | [doc](https://developer.ebay.com/api-docs/buy/browse/resources/item_summary/methods/search)
+GET         | getItem       | Retrieve the complete details of a specific item.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/browseApi.js#L16) | [doc](https://developer.ebay.com/api-docs/buy/browse/resources/item/methods/getItem)
+GET         | getItemsByItemGroup        | Retrieve all the individual items in a group.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/browseApi.js#L55) | [doc](https://developer.ebay.com/api-docs/buy/browse/resources/item/methods/getItemsByItemGroup#uri.item_group_id)
+GET         | getItemByLegacyId       | Returns the RESTful item ID, which can then be used in any of other Buy API methods.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/finding.js#L21) | [doc](https://developer.ebay.com/devzone/finding/callref/finditemsbykeywords.html)
+GET         | searchByImage       | Returns the RESTful item ID, which can then be used in any of other Buy API methods.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/searchApi.js#L93) | [doc](https://developer.ebay.com/api-docs/buy/browse/resources/search_by_image/methods/searchByImage)
+GET         | getMostWatchedItems       | Retrieves data for items with the highest watch counts for the entire site or for a specific category.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/merchandisingApi.js#L15) | [doc](https://developer.ebay.com/DevZone/merchandising/docs/CallRef/getSimilarItems.html)
+GET         | getSimilarItems       | Retrieves recommended similar items for a specified item. | [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/searchApi.js#L93) | [doc](https://developer.ebay.com/api-docs/buy/browse/resources/search_by_image/methods/searchByImage)
+GET         | getItemAspectsForCategory       | Retrieve an array of aspects that are appropriate for describing items in a specified category.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/finding.js#L40) | [doc](https://developer.ebay.com/api-docs/commerce/taxonomy/resources/methods)
+GET         | getDefaultCategoryTreeId       | Retrieve the default category tree reference for a specific eBay marketplace.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/finding.js#L40) | [doc](https://developer.ebay.com/api-docs/commerce/taxonomy/resources/methods)
+GET         | getCategoryTree       | Retrieve the complete category tree for category id.| [Example](https://github.com/pajaydev/ebay-node-api/blob/master/demo/finding.js#L40) | [doc](https://developer.ebay.com/api-docs/commerce/taxonomy/resources/methods)
+
 ## Examples
 
 ```javascript