Add new page for built-in tools

src/SUMMARY.md

@@ -10,6 +10,7 @@
 	* [Git configuration](configuration/git.md)
 	* [Repository information](configuration/repository.md)
 	* [Beyond Compare configuration](configuration/beyond-compare.md)
+* [Included Tools](tools.md)
 * [Commits](commits.md)
 	* [Fixing commits](commits/fixing.md)
 * [Stashing](stashing.md)

src/tools.md

@@ -0,0 +1,13 @@
+# Included Tools
+
+```bash
+# Simple GUI for Git.
+git gui
+```
+
+```bash
+# Simple GUI showing current branch commits.
+gitk
+# Simple GUI showing all branches and commits.
+gitk --all
+```