Break util.cr into multiple files

src/util/util.cr

@@ -0,0 +1,33 @@
+require "big"
+
+IMGS_PER_PAGE     = 5
+UPLOAD_URL_PREFIX = "/uploads"
+STATIC_DIRS       = ["/css", "/js", "/img", "/favicon.ico"]
+
+def random_str
+  UUID.random.to_s.gsub "-", ""
+end
+
+# Works in all Unix systems. Follows https://github.com/crystal-lang/crystal/
+#   blob/master/src/crystal/system/unix/file_info.cr#L42-L48
+def ctime(file_path : String) : Time
+  res = LibC.stat(file_path, out stat)
+  raise "Unable to get ctime of file #{file_path}" if res != 0
+
+  {% if flag?(:darwin) %}
+    Time.new stat.st_ctimespec, Time::Location::UTC
+  {% else %}
+    Time.new stat.st_ctim, Time::Location::UTC
+  {% end %}
+end
+
+def register_mime_types
+  {
+    ".zip" => "application/zip",
+    ".rar" => "application/x-rar-compressed",
+    ".cbz" => "application/vnd.comicbook+zip",
+    ".cbr" => "application/vnd.comicbook-rar",
+  }.each do |k, v|
+    MIME.register k, v
+  end
+end