hide #prepare from api.

src/db/connection.cr

@@ -15,8 +15,6 @@ module DB
   # Also override `#last_insert_id` to allow safe access to the last inserted id through this connection.
   #
   abstract class Connection
-    # TODO add IDLE status, for connection ppool management.
-
     @closed = false
 
     # Closes this connection.
@@ -36,7 +34,7 @@ module DB
       close unless closed?
     end
 
-    # Returns an `Statement` with the prepared `query`
+    # :nodoc:
     abstract def prepare(query) : Statement
 
     include QueryMethods

src/db/database.cr

@@ -29,10 +29,7 @@ module DB
       @connection
     end
 
-    # Prepares a `Statement`. The Statement must be closed explicitly
-    # after is not longer in use.
-    #
-    # Usually `#exec`, `#query` or `#scalar` should be used.
+    # :nodoc:
     def prepare(query)
       connection.prepare(query)
     end