Avoid repeat anchors for images

See https://git.autonomic.zone/coop-cloud/abra/issues/172.

compose.yml

@@ -50,7 +50,7 @@ services:
         hard: -1
 
   web:
-    image: &image decentral1se/hometown:v1.0.5_3.4.0_openid-sso
+    image: decentral1se/hometown:v1.0.5_3.4.0_openid-sso
     command: bash -c "rm -f /mastodon/tmp/pids/server.pid; bundle exec rails s -p 3000"
     networks: &bothNetworks
       - proxy
@@ -211,7 +211,7 @@ services:
       - http_proxy # yes, this should be lowercase
 
   streaming:
-    image: *image
+    image: decentral1se/hometown:v1.0.5_3.4.0_openid-sso
     command: node ./streaming
     configs: *configs
     entrypoint: *entrypoint
@@ -244,7 +244,7 @@ services:
     volumes: *appVolume # used to make sure this volume is created
 
   sidekiq:
-    image: *image
+    image: decentral1se/hometown:v1.0.5_3.4.0_openid-sso
     secrets: *secrets
     command: bundle exec sidekiq
     configs: *configs