Adding eslint rules

.eslintrc

@@ -1,7 +1,10 @@
 {
-  "extends": "airbnb",
+  "extends": [
+    "airbnb",
+    "plugin:flowtype/recommended"
+  ],
   "parser": "babel-eslint",
-  "plugins": ["jest"],
+  "plugins": ["jest", "flowtype"],
   "rules": {
     "react/jsx-filename-extension": [1, { "extensions": [".js", ".jsx"] }],
     "react/forbid-prop-types": [1, { "forbid": ["object", "any"] }],
@@ -25,7 +28,67 @@
     "import/prefer-default-export": 0,
     "jsx-a11y/label-has-for": 0,
     "indent": ["error", 2],
-    "no-console": ["error", { "allow": ["warn", "error"] }]
+    "no-console": ["error", { "allow": ["warn", "error"] }],
+    "flowtype/boolean-style": [
+      2,
+      "boolean"
+    ],
+    "flowtype/define-flow-type": 1,
+    "flowtype/delimiter-dangle": [
+      2,
+      "never"
+    ],
+    "flowtype/generic-spacing": [
+      2,
+      "never"
+    ],
+    "flowtype/no-primitive-constructor-types": 2,
+    "flowtype/no-types-missing-file-annotation": 2,
+    "flowtype/no-weak-types": 2,
+    "flowtype/object-type-delimiter": [
+      2,
+      "comma"
+    ],
+    "flowtype/require-parameter-type": 2,
+    "flowtype/require-return-type": [
+      2,
+      "always",
+      {
+        "annotateUndefined": "never"
+      }
+    ],
+    "flowtype/require-valid-file-annotation": 2,
+    "flowtype/semi": [
+      2,
+      "always"
+    ],
+    "flowtype/space-after-type-colon": [
+      2,
+      "always"
+    ],
+    "flowtype/space-before-generic-bracket": [
+      2,
+      "never"
+    ],
+    "flowtype/space-before-type-colon": [
+      2,
+      "never"
+    ],
+    "flowtype/type-id-match": [
+      2,
+      "^([A-Z][a-z0-9]+)+Type$"
+    ],
+    "flowtype/union-intersection-spacing": [
+      2,
+      "always"
+    ],
+    "flowtype/use-flow-type": 1,
+    "flowtype/valid-syntax": 1
+  },
+  "settings": {
+    "flowtype": {
+      "onlyFilesWithFlowAnnotation": false
+    }
   },
   "env": {
     "jest/globals": true,