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 # DayFlags
-A simple service to flag days
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+A simple service to flag days. This repo is currently work in progress
+
+## Idea
+This service helps to mark days. It can be used to collect events in the past or to announce events in the future.
+
+## Definition
+### Realm
+A realm is a defined area for the other objects. Everything within a realm is unique.
+
+### FlagType
+FlagTypes that define the allowed DayFlags. A FlagType can occur in a FlagGroup. 
+
+### FlagGroup
+A FlagGroup is a grouping of multiple FlagTypes. It can be used for queries. There is a flag if only one FlagType of the group is allowed on a date.
+
+### DayFlag
+DayFlags are used to specify the occurrence of a FlagType on a calendar date.
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