Add .editorconfig

.editorconfig

@@ -0,0 +1,17 @@
+# This file is for unifying the coding style for different editors and IDEs
+# editorconfig.org
+
+root = true
+
+[*]
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[**.{js,json,md}]
+indent_style = space
+indent_size = 2
+
+[**.html]
+indent_style = tab