add editorconfig

.editorconfig

@@ -0,0 +1,13 @@
+root = true
+
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 2
+trim_trailing_whitespace = true
+end_of_line = lf
+insert_final_newline = true
+
+[*.md]
+# two spaces at the end of a line create a linebreak
+trim_trailing_whitespace = false