Create time_converter.cr

Adds time converter for parsing time strings

src/schema/ext/time/time_converter.cr

@@ -0,0 +1,23 @@
+require "../../annotations"
+
+@[Schema::Definition::Scalar]
+struct Time
+  module TimeConverter
+    # Put *value* as a time timestamp into the *builder* at *key*.
+    def self.to_http_param(value : Time, builder : HTTP::Params::Builder, key : String)
+      builder.add(key, to_http_param(value))
+    end
+
+    # Return *value* as a time timestamp string.
+    def self.to_http_param(value : Time)
+      value.to_unix.to_s
+    end
+
+    # Parse `Time` from an HTTP param as time timestamp.
+    def self.from_http_param(value : String) : Time
+      Time.parse(value, "%Y-%m-%d %H:%M:%S %z", Time::Location::UTC)
+    rescue ArgumentError
+      raise TypeCastError.new
+    end
+  end
+end