update README

README.md

@@ -66,6 +66,9 @@ When multiple tables are present, you will be prompted to select the table you w
 
 <img src="assets/06.gif" width=500>
 
+You can delegate the editing of a cell to your external editor set in the `$EDITOR` environment variable.
+<img src="assets/07.gif" width=500>
+
 ## ⌨️ Key Bindings
 
 | Key            | Action            |
@@ -81,6 +84,7 @@ When multiple tables are present, you will be prompted to select the table you w
 | `g`/`home`     | Go to start       |
 | `G`/`end`      | Go to end         |
 | `i`            | Insert mode       |
+| `I`            | Open `$EDITOR`    |
 | `esc`/`ctrl+c` | Normal mode       |
 | `o`/`vo`       | Add row/column    |
 | `dd`/`vd`      | Delete row/column |

table.go

@@ -198,7 +198,7 @@ func (k keyMap) FullHelp() [][]key.Binding {
 	return [][]key.Binding{
 		{k.lineUp, k.lineDown, k.left, k.right, k.pageUp, k.pageDown,
 			k.halfPageUp, k.halfPageDown, k.gotoTop, k.gotoBottom},
-		{k.insertMode, k.normalMode, k.addRowCol, k.delRowCol,
+		{k.insertMode, k.editor, k.normalMode, k.addRowCol, k.delRowCol,
 			k.yank, k.paste, k.quit, k.help},
 	}
 }