Add SQL database reading to documentation (#464)

Author: zaleslaw

docs/StardustDocs/d.tree

@@ -44,6 +44,7 @@
         </toc-element>
         <toc-element topic="io.md">
             <toc-element topic="read.md"/>
+            <toc-element topic="readSqlDatabases.md"/>
             <toc-element topic="write.md"/>
         </toc-element>
         <toc-element topic="info.md">

docs/StardustDocs/sitemap.xml

@@ -417,6 +417,11 @@
   <lastmod>2023-06-26T12:33:14+00:00</lastmod>
   <priority>0.51</priority>
 </url>
+    <url>
+        <loc>https://kotlin.github.io/dataframe/readSqlDatabases.html</loc>
+        <lastmod>2023-06-26T12:33:14+00:00</lastmod>
+        <priority>0.51</priority>
+    </url>
 <url>
   <loc>https://kotlin.github.io/dataframe/createdataframe.html</loc>
   <lastmod>2023-06-26T12:33:14+00:00</lastmod>
@@ -714,4 +719,4 @@
 </url>
 
 
-</urlset>
+</urlset>

docs/StardustDocs/topics/io.md

@@ -3,6 +3,8 @@
 When you work with data, you have to [read](read.md) it from disk or from remote URLs and [write](write.md) it on disk.
 This section describes how to do it. For now, CSV, TSV, JSON, XLS, XLSX, Apache Arrow formats are supported.
 
+The reading from SQL databases is also supported. Read [here](readSqlDatabases.md) to know more.
+
 Working with [Apache Spark](https://spark.apache.org/) directly from Kotlin DataFrame is not possible at the time of 
 writing. However, there is a [Kotlin Spark API](https://github.com/Kotlin/kotlin-spark-api) which we can recommend in
 the meantime. If you do want to work with data from Spark in Kotlin DataFrame, we recommend exporting your data to CSV or

docs/StardustDocs/topics/read.md

@@ -3,6 +3,8 @@
 
 The Kotlin DataFrame library supports CSV, TSV, JSON, XLS and XLSX, and Apache Arrow input formats.
 
+The reading from SQL databases is also supported. Read [here](readSqlDatabases.md) to know more.
+
 The `.read()` function automatically detects the input format based on a file extension and content:
 
 ```kotlin