docs(couchbase-lite): update usage (#2059)

* adding detailed usage for couchbase lite

* added get url method

* create database method added

* delete database method added

* get all database method added

* space added in comments

* comments added unwanted import removed

* whitespaces added

* usage added in commented section

* get all documents,create document methods added

* spell mistake corrected

* getAllDocs Method Usage added

* create document example added

* update document example added

* delete document example added

src/@ionic-native/plugins/couchbase-lite/index.ts

@@ -45,7 +45,6 @@ import { Injectable } from '@angular/core';
  *           return Observable.throw(error.json() || 'Couchbase Lite error');
  *        })
  * }
- *
  * getAllDbs() {
  *      let url = this.getUrl();
  *      url = url+'_all_dbs';
@@ -56,6 +55,59 @@ import { Injectable } from '@angular/core';
  *           return Observable.throw(error.json() || 'Couchbase Lite error');
  *        })
  * }
+ * // DOCUMENTS //
+ * getAllDocuments(database_name:string){
+ *      let url = this.getUrl();
+ *      // include_docs=true will include a doc inside response, it is false by default
+ *      url = url + database_name + '/_all_docs?include_docs=true';
+ *      return this._http
+ *        .get(url)
+ *        .map(data => { this.results = data['results'] })
+ *        .catch((error:any) => {
+ *           return Observable.throw(error.json() || 'Couchbase Lite error');
+ *        })        .
+ * }      
+ * createDocument(database_name:string,document){   
+ *      let url = this.getUrl();
+ *      url = url + database_name;
+ *      return this._http
+ *        .post(url,document)
+ *        .map(data => { this.results = data['results'] })
+ *        .catch((error:any) => {
+ *           return Observable.throw(error.json() || 'Couchbase Lite error');
+ *        })        .
+ * }
+ * let document = {
+ *    _id:'You can either specify the document ID (must be string) else couchbase generates one for your doc',
+ *    data:{name:'sandman',age:25,city:pune}
+ *  }
+ * createDocument('justbe', document);
+ * // successful response
+ * { "id": "string","rev": "string","ok": true }
+ * updateDocument(database_name:string,document){    
+ *      let url = this.getUrl();
+ *      url = url + database_name + '/' + document._id;     
+ *      return this._http
+ *        .put(url,document)
+ *        .map(data => { this.results = data['results'] })
+ *        .catch((error:any) => {
+ *           return Observable.throw(error.json() || 'Couchbase Lite error');
+ *        })        .
+ * }
+ * // for updation of document your document must contain most recent rev(revision) id.
+ * // for each updation of document new rev id is get generated
+ * // successful response
+ * { "id": "string","rev": "string(new revision id)","ok": true }
+ * deleteDocument(database_name:string,document){
+ *      let url = this.getUrl();
+ *      url = url + database_name + '/' + document._id +'?rev='+doc._rev;
+ *      return this._http
+ *        .delete(url)
+ *        .map(data => { this.results = data['results'] })
+ *        .catch((error:any) => {
+ *           return Observable.throw(error.json() || 'Couchbase Lite error');
+ *        })        .
+ * }
  *
  *
  * ```