docs: add COMMON_ISSUES and more examples to the README.md

Author: JCMais

COMMON_ISSUES.md

@@ -0,0 +1,7 @@
+## Error: SSL peer certificate or SSH remote key was not Ok
+
+You need to set either [`CAINFO`](https://curl.haxx.se/libcurl/c/CURLOPT_CAINFO.html) or [`CAPATH`](https://curl.haxx.se/libcurl/c/CURLOPT_CAPATH.html) options, or disable SSL verification with [`SSL_VERIFYPEER`](https://curl.haxx.se/libcurl/c/CURLOPT_SSL_VERIFYPEER.html) which is not recommended.
+
+The certificate file can be obtained in multiple ways:
+1. Downloaded from https://curl.haxx.se/docs/caextract.html
+2. Creating a file with the contents of `tls.rootCertificates`, which was added with Node.js `v12.3.0`

README.md

@@ -39,9 +39,11 @@
   - [Simple Request - Async / Await](#simple-request---async--await)
   - [Simple Request](#simple-request)
     - [Setting HTTP headers](#setting-http-headers)
-  - [MultiPart Upload / HttpPost libcurl Option](#multipart-upload--httppost-libcurl-option)
+  - [Form Submission (Content-Type: application/x-www-form-urlencoded)](#form-submission-content-type-applicationx-www-form-urlencoded)
+  - [MultiPart Upload / HttpPost libcurl Option (Content-Type: multipart/form-data)](#multipart-upload--httppost-libcurl-option-content-type-multipartform-data)
 - [Benchmarks](#benchmarks)
 - [API](#api)
+- [Common Issues](#common-issues)
 - [Supported Libcurl Versions](#supported-libcurl-versions)
 - [For Enterprise](#for-enterprise)
 - [Detailed Installation](#detailed-installation)
@@ -77,6 +79,19 @@ const { curly } = require('node-libcurl');
 const { statusCode, data, headers } = await curly.get('http://www.google.com')
 ```
 
+Any option can be passed using their `FULLNAME` or a `lowerPascalCase` format:
+```javascript
+const querystring = require('querystring');
+const { curly } = require('node-libcurl');
+
+const { statusCode, data, headers } = await curly.post('http://httpbin.com/post', {
+  postFields: querystring.stringify({
+    field: 'value',
+  }),
+  // can use `postFields` or `POSTFIELDS`
+})
+```
+
 ### Simple Request
 ```javascript
 const { Curl } = require('node-libcurl');
@@ -108,7 +123,25 @@ curl.setOpt(Curl.option.HTTPHEADER,
   ['Content-Type: application/x-amz-json-1.1'])
 ```
 
-### MultiPart Upload / HttpPost libcurl Option
+### Form Submission (Content-Type: application/x-www-form-urlencoded)
+```javascript
+const querystring = require('querystring');
+const { Curl } = require('node-libcurl');
+
+const curl = new Curl();
+const close = curl.close.bind(curl);
+
+curl.setOpt(Curl.option.URL, '127.0.0.1/upload');
+curl.setOpt(Curl.option.POST, true)
+curl.setOpt(Curl.option.POSTFIELDS, querystring.stringify({
+  field: 'value',
+}));
+
+curl.on('end', close);
+curl.on('error', close);
+```
+
+### MultiPart Upload / HttpPost libcurl Option (Content-Type: multipart/form-data)
 
 ```javascript
 const { Curl } = require('node-libcurl');
@@ -139,6 +172,10 @@ Almost all [CURL options](https://curl.haxx.se/libcurl/c/curl_easy_setopt.html)
 
 For more usage examples check the [examples folder](./examples).
 
+## Common Issues
+
+See [COMMON_ISSUES.md](./COMMON_ISSUES.md)
+
 ## Supported Libcurl Versions
 
 The addon is only tested against libcurl version `7.50.0` and the latest one available.