Added eslint, clean autogenerated App.js, prepared sidebar for markup

Author: dmitryt

Diff for: .editorconfig

@@ -0,0 +1,16 @@
+# EditorConfig is awesome: http://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+# Unix-style newlines with a newline ending every file
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+
+# Matches multiple files with brace expansion notation
+# Set default charset
+[*.{js,json}]
+indent_size = 2
+indent_style = space

Diff for: .eslintrc.js

@@ -0,0 +1,3 @@
+module.exports = {
+  extends: "react-app"
+};

Diff for: .gitignore

@@ -19,3 +19,5 @@
 npm-debug.log*
 yarn-debug.log*
 yarn-error.log*
+
+yarn.lock