Web based software for content approvals

We are a social media company and we need a software to manage approval workflow for the social media content. We need a web based software tool which would manage approvals as defined below. 1. A user (Initiator) will initiate the workflow, by adding the following content:- a. Image / images, or videos b. Text (Description) c. Customer name (From dropdown) d. Select Approver (From dropdown) 2. The user uploading the content (Initiator) could mark any user as his / her approver. 3. The approver could:- a. Change image / video, b. Change text description c. Approve / Reject content, or send to another user for approval. 4. When one of the users in the chain finally approves, everyone gets a notification and an approved version. 5. A history can be maintained of the edits with usernames and timestamp. 6. User can see history of past work – a. Pending approval (still in work flow), and pending with whom b. Approved / rejected content c. Draft content (Yet to be sent to approver) d. Received for approval – Content sent by other users for approval User Roles 7. A user has no specific role. The same user could be a normal user, or approver. 8. Each user will have a default approver. However, he can select any other approver from dropdown. Admin 9. There will be a page to add / remove users, with their details (login ID, name), his default approver (from existing users). 10. There will be a page to add customer names, address, content person, contact details 11. Login / authentication – Google integration Optional 12. Offline / Online mode feature - Allows users to work on the app when offline. Syncs when online with latest data.