Added composeClear function in redux

• Added:
- composeClear function in redux

app/javascript/gabsocial/actions/compose.js

@@ -68,6 +68,8 @@ export const COMPOSE_SCHEDULED_AT_CHANGE = 'COMPOSE_SCHEDULED_AT_CHANGE';
 
 export const COMPOSE_RICH_TEXT_EDITOR_CONTROLS_VISIBILITY = 'COMPOSE_RICH_TEXT_EDITOR_CONTROLS_VISIBILITY'
 
+export const COMPOSE_CLEAR = 'COMPOSE_CLEAR'
+
 const messages = defineMessages({
   uploadErrorLimit: { id: 'upload_error.limit', defaultMessage: 'File upload limit exceeded.' },
   uploadErrorPoll:  { id: 'upload_error.poll', defaultMessage: 'File upload not allowed with polls.' },
@@ -335,6 +337,12 @@ export function submitComposeSuccess(status) {
   };
 };
 
+export function clearCompose() {
+  return {
+    type: COMPOSE_CLEAR,
+  };
+};
+
 export function submitComposeFail(error) {
   return {
     type: COMPOSE_SUBMIT_FAIL,