[Event Draft. Step 3. Categories] As a user I want to choose a category for the event, so that I can choose for my event

As a user I want to choose a category for the event so that I can choose my event

**Date Time**
04/06/2022

**Pre-requisites**
Event creation is implemented.

**Description**
1. The system navigates the user to the Step 3 with the following fields:

- Title: "The category of the event";
- Boxes with categories, the same as already exist on sign up form (mandatory);
- List of hashtags (optional);
- Button "Back";
- Button "Save".

2. When no category is selected the system doesn't display any hashtags;
3. When a user selects a category, the system displays appropriate hashtags;
4. When a user clicks the button "Back" the system navigates the user to the previous Step 2;
5. When a user clicks the button Save" the system checks that whether all mandatory fields are fulfilled:
- If not displays the warning message " is required";
- If yes the system saves the event as a draft.

**Acceptance criteria**
| | |
|:-----------:|:-----------:|
| Scenario | The user completes the Step 3 of "Create Event" form |
| Given | The user is on the Step 3 of "Create Event" form |
| When | The user fills all fields on the Step 3 |
| And | The user clicks on button "Save" |
| Then | The system validates whether all mandatory fields on the Step 3 are fulfilled |
| And | The system validates whether all fields have passed the usability requirements or not |
| Given | The user is on the Step 2 of "Create Event" form |
| When | The system successfully validates all fields on the Step 1 |
| Then | The system saves the event details |
| And | The system navigates the user to the Draft page |

**Additional context**

**Epic link** E.g.: Epic #1119