Add linting with eslint and prettier

Author: timomeh

.eslintrc.json

@@ -0,0 +1,8 @@
+{
+  "parser": "babel-eslint",
+  "extends": ["plugin:prettier/recommended"],
+  "plugins": ["react", "react-native"],
+  "env": {
+    "node": true
+  }
+}

.gitignore

@@ -0,0 +1,2 @@
+/node_modules
+npm-debug.log*

.prettierrc.json

@@ -0,0 +1,4 @@
+{
+  "semi": false,
+  "singleQuote": true
+}