Add chapter about tagging

Signed-off-by: trivernis <trivernis@protonmail.com>

_docs/40_tagging.md

@@ -2,6 +2,48 @@
 layout: doc
 title: Tagging
 sort_index: 40
-draft: true
+draft: false
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+The main feature of mediarepo is associating tags with files. 
+A tag describes a feature of a file or some metadata about it.
+There's unnamespaced tags, e.g. `summer` or `frog` and namespaced
+tags (prepended and separated from the tag by a colon)m e.g. `weather:sunny`
+or `author:trivernis`.
+Tags enable you to search for files more accurately and sort them according to tag namespaces.
+
+To assign tags we're opening a new *Files* tab. You can also stay in the import
+tab from the previous step as we're probably spending more time in the *Files* tab anyway
+we're switching to it in this walkthrough.
+
+Use the **+** icon next to the rightmost tab to open a new tab and select *Files*.
+
+![](/assets/images/mediarepo-new-tab-files.png)
+
+This tab looks very similar to the import tab and the layout is mostly the same.
+On the left side you've got search and sorting options but for tagging we don't need those
+right now. To make identifying features of the images easier let's switch to the gallery view.
+To open this view you can double click an image in the gallery view or select it and press `<Enter>`
+or right click it and select *Open*.
+
+![](/assets/images/mediarepo-files-open-image.png)
+
+A full view of the selected image will open. To edit tags we have to switch to the *Edit Tags* mode
+of the side menu (1).
+
+![](/assets/images/mediarepo-edit-tags-gallery.png)
+
+Now you can assign tags to the selected image by entering them in the text field (2). When entering
+a tag and pressing `<Enter>` or the button next to the input field it gets assigned to the file. When
+entering it again and pressing enter again it will be removed from this image. This is because
+the default mode for assinging tags is the *Toggle* mode which add a tag when it's not assigned
+ and removes it when it is. you can change the mode in the mode selection drop-down (3). Tags can also be deleted
+ by pressing the **-** button next to the tag in the *Edit Tags* list.
+If you want to assign tags to multiple files at once you can exit the gallery view by pressing the **x** in the top
+right corner or pressing `<Escape>` twice in quick succession.
+
+In the grid view you can select multiple files by first selecting one file and then while pressing `<Shift>` or 
+`<Ctrl>` selecting another. You can also use `<Ctrl> + <A>` to select all files. The *Edit Tags* mode of the side menu
+will only be visible when at least one file is selected.
+
+![](/assets/images/edit-tags-grid-multiple.png)

_docs/90_repo_configuration.md

@@ -1,7 +1,7 @@
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 layout: doc
 title: Repository Configuration
-sort_index: 50
+sort_index: 90
 draft: true
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