Update roadmap.md

Author: olekscode

roadmap.md

@@ -1,8 +1,29 @@
 # DataFrame Roadmap
 
-In this document, I describe the functionality that we want to add to DataFrame in the nearest future. For the specific features that need to be added, please check the [issues](https://github.com/PolyMathOrg/DataFrame/issues).
+In this document, I describe the functionality that we want to add to DataFrame or existing functionality that we want to improve in the nearest future. For the specific features that need to be added, please check the [issues](https://github.com/PolyMathOrg/DataFrame/issues).
+
+## Improvements
+
+* Improve DataFrameTypeDetector
+* Improve inspector view (FastTable)
+
+## New functionality
 
 * Handling missing values
+* Joins
 * Time series
+* Support for more file formats
+
+## Experimental
+
+* Database backend
+
+## Documentation
+
+* Examples
+* Tutorials
+
+## Tools around DataFrame
 
-We should find time to go over the documentation of pandas and R and create the complete list of everything we don't have.
+* Datasets
+* DataFrame editor