Add a PlantUML class diagram (#129)

README.md

@@ -186,6 +186,12 @@ Therefore we use a simple
 [script](https://github.com/slowtec/openfairdb/blob/master/scripts/backup-sqlite.sh)
 that copies the DB file once a day.
 
+# Domain Model
+
+*![The rendered class diagram should appear here!](http://www.plantuml.com/plantuml/svg/RLJ1Yjim4BtxAqIEWLtQQp1XswM7maAXsvx3n1uKiVQCaSRj9gN_NbLZErQK76BhlQStencDduA0bx7lgghf80JpgMqznkUVoiHVu-IyCw_Y7La5U2JnEHR48qe6NTomhF_Erf-F_5vL___Dzk5XRpQ1HpaTVcCGyt5ZdfbzwmW4rnfY7pK8XMPb-ZeUG-FT88x9r3MInBJt-wegoCrsOv9jzFePq9kT2SeVCHXXKvTxjlC6pL_3FeEWPN_EmaqKztt4CcR6eiqI_pk88nipQ9GCPcL10erCJS0UN9ULzyGz3c0n0mKx74vCM5R-MhR9iWFPcHSG9sEBYf2D29DLQDdwXIGxvMpW6gIG9-1wi7WOVNS7xHozPLGCeDRQalHOYXfheg_kWi7KfV87s2WIi0kxj6aktYtymj7JCIq7-tNRf8H4RN556eyWceXAxYUYR9b83XU9NDVpswJzyFWOvTD0tf831vUMTwVYcxT0xg8RYkR1u0x2RqZhRcHRYXFstA87mTKbrVjRkZTCWk_vzy0dxSvyZPH5dx30es-mk13tPqHZrqjixZ157ljby5AcnJXg3wzmELCQEydc7YN_gdf2QiU--mS0)*
+
+Note: Currently the rendered class diagram must be updated manually by uploading the contents of the file [classes.puml](classes.puml) to the [PlantUML Online Editor](http://www.plantuml.com/plantuml/uml/) and replace the link for the rendered diagram with one of the generated URLs.
+
 # License
 
 Copyright (c) 2015 - 2018 Markus Kohlhase

classes.puml

@@ -0,0 +1,84 @@
+@startuml
+
+class Address {
+    city: String
+    country: String
+    street: String
+    zip: String
+}
+
+class Bbox
+
+Bbox *--> "south_west 1" Coordinate
+Bbox *--> "north_east 1" Coordinate
+
+class BboxSubscription <<entity>>
+
+BboxSubscription "*" --> "1" User : subscribes to <
+BboxSubscription *--> "1" Bbox
+
+class Category <<entity>>
+
+class Comment <<entity>>
+
+Comment "1" --> "1" Rating : comments >
+
+class Contact {
+    email: String
+    homepage: String
+    telephone: String
+}
+
+class Coordinate {
+    lat: Latitude
+    lng: Longitude
+}
+
+class Entry <<entity>> {
+    license: String
+    image_url: String
+    image_link_url: String
+}
+
+Entry "*" -- "*" Category : categorizes <
+Entry "*" -- "*" Tag : tags <
+Entry *--> "1" Contact
+Entry *--> "1" Location
+
+class Event <<entity>>
+
+Event "1" --> "1" User : creates <
+Event "*" -- "*" Tag : tags <
+Event *--> "1" Contact
+Event *--> "1" Location
+
+class Location
+
+Location *--> "0..1" Address
+Location *--> "position 1" Coordinate
+
+class Organization <<entity>> {
+    api_token: String
+}
+
+Organization "*" -- "*" Tag : moderates >
+
+class Rating <<entity>> {
+    context: String
+    rating: Integer
+    source: String
+}
+
+Entry "1" --> "1" Rating : rates <
+
+class Role <<enum>>
+
+class Tag <<entity>>
+
+class User <<entity>> {
+    email: String
+}
+
+User *--> "1" Role
+
+@enduml