Prevent final user to include Clear::Model on struct-like object, since

it behave strangely

src/clear/model/model.cr

@@ -22,6 +22,9 @@ module Clear::Model
   # The overload are shown in this case, but not in the case the constructors
   # are directly defined without the included block.
   macro included
+    {% raise "Do NOT include Clear::Model on struct-like objects.\n"+
+      "It would behave very strangely otherwise." unless @type < Reference %}
+
     getter cache : Clear::Model::QueryCache?
 
     def initialize(@persisted = false)

templates/kemal/src/db/init.ecr

@@ -8,5 +8,6 @@ def self.init_db
     Clear::SQL.init(CLEAR_DB_CONFIG["uri"].as_s)
   rescue DB::ConnectionRefused
     puts "FATAL: Connection to the database (#{uri}) has been refused"
+    exit
   end
 end