add editorconfig for emqx

.editorconfig

@@ -0,0 +1,27 @@
+# EditorConfig is awesome: https://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+# Unix-style newlines with a newline ending every file
+[*]
+charset = utf-8
+end_of_line = lf
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+
+# Matches multiple files with brace expansion notation
+# Set default charset
+[*.{erl, src, hrl}]
+indent_style = space
+indent_size = 4
+
+# Tab indentation (no size specified)
+[Makefile]
+indent_style = tab
+
+# Matches the exact files either package.json or .travis.yml
+[{.travis.yml}]
+indent_style = space
+indent_size = 2