fix: add className props

stories/Button.tsx

@@ -7,6 +7,7 @@ import { Spinner } from './Spinner';
 export interface ButtonProps {
   [key: string]: any;
   children: ReactNode;
+  className?: string;
   disabled?: boolean;
   inverse?: boolean;
   loading?: boolean;
@@ -20,6 +21,7 @@ export interface ButtonProps {
  */
 export const Button: FunctionComponent<ButtonProps> = ({
   children,
+  className,
   disabled = false,
   inverse = false,
   loading = false,
@@ -39,6 +41,7 @@ export const Button: FunctionComponent<ButtonProps> = ({
         isDisabled && styles.disabled,
         loading && styles.loading,
         inverse && styles.inverse,
+        className,
       )}
       onClick={() => {
         if (!isDisabled) onClick()

stories/Checkbox.tsx

@@ -8,6 +8,8 @@ export interface CheckboxProps {
    */
   checked?: boolean;
 
+  className?: string;
+
   /**
    * Disables the component.
    */
@@ -21,6 +23,7 @@ export interface CheckboxProps {
 
 export const Checkbox: FunctionComponent<CheckboxProps> = ({
   checked = false,
+  className,
   disabled = false,
   onChange,
 }: CheckboxProps) => {
@@ -41,6 +44,7 @@ export const Checkbox: FunctionComponent<CheckboxProps> = ({
         styles.checkbox,
         internallyChecked && styles.checked,
         disabled && styles.disabled,
+        className,
       )}
       onClick={updateValue}
     >

stories/Icon.tsx

@@ -1,3 +1,4 @@
+import classNames from 'classnames';
 import React, { FunctionComponent } from 'react';
 import { FaFacebookF, FaTwitter, FaShare, FaHeart } from 'react-icons/fa';
 import { GoPlus } from 'react-icons/go';
@@ -14,18 +15,23 @@ export const ICON_MAP = {
 };
 
 export interface IconProps {
+  className?: string;
   icon: keyof typeof ICON_MAP;
 }
 
 export const Icon: FunctionComponent<IconProps> = ({
+  className,
   icon,
   ...props
 }: IconProps) => {
   const MappedIcon = ICON_MAP[icon];
 
   return (
     <MappedIcon
-      className={styles.icon}
+      className={classNames(
+        styles.icon,
+        className,
+      )}
       {...props}
     />
   )