add editorconfig

.editorconfig

@@ -0,0 +1,17 @@
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+charset = utf-8
+indent_style = space
+indent_size = 2
+
+[{Gemfile,Rakefile,Guardfile,Procfile}]
+trim_trailing_whitespace = true
+
+[*.{js,hbs,rb,rake,ru,erb,haml,scss,sh,md}]
+trim_trailing_whitespace = true
+
+[*.yml]
+trim_trailing_whitespace = false