Add Form to fill in order to add an Activity

[wladyDE]

After clicking on the plus Button, it should be possible to add an Activity.
You need just to choose a place on the map.
After you click on the map, you have to fill the form out:
-Time
-Activity
-Max number of people
-Description

After that the marker should appears on the map.
If you click on the marker it shows that info

[wladyDE]

I am focusing firstly on the logic. Styles and design can be done later...