kahlan: add page (#3162)

pages/common/kahlan.md

@@ -0,0 +1,20 @@
+# kahlan
+
+> A unit and Behaviour Driven Development test framework for PHP.
+> More information: <https://kahlan.github.io>.
+
+- Run all specifications in the "spec" directory:
+
+`kahlan`
+
+- Run specifications using a specific configuration file:
+
+`kahlan --config={{path/to/configuration_file}}`
+
+- Run specifications and output using a reporter:
+
+`kahlan --reporter={{dot|bar|json|tap|verbose}}`
+
+- Run specifications with code coverage (detail can be between 0 and 4):
+
+`kahlan --coverage={{detail_level}}`