added readme

Author: janxb

README.md

@@ -0,0 +1,27 @@
+# PHP iCAL Viewer
+
+## Parameters
+
+### CALENDAR_LANGUAGE
+Which language are the calendar events in?
+### CALENDAR_URLS
+The `.ics` URLs of your calendars. For multiple entries, input them comma-separated.
+### CALENDAR_NAMES
+The names for your calendars. For multiple entries, input them comma-separated.
+The values have to be in the same order than `CALENDAR_URLS`
+### CALENDAR_COLORS
+The colors for your calendars. For multiple entries, input them comma-separated.
+The values have to be in the same order than `CALENDAR_URLS`
+### CALENDAR_PASSWORDS
+For protecting access to the calendar, you can define multiple passwords.
+When opening the page, a password popup is displayed. The password is stored
+for a longer timeframe in a browser cookie. Multiple values can be defined comma-separated.
+### CALENDAR_CACHE_TTL
+How long should fetched `.ics` files be cached locally, until they are refreshed from
+the remote source? Value is in seconds.
+### APP_SECRET
+A random string used by the Symfony framework.
+### CALENDAR_PUBLIC_AVAILABILITY
+Normally, when `CALENDAR_PASSWORDS` is set, the calendar can't be accessed by the public.
+If you enable this option, a limited view with available / not available times is 
+shown instead. This way you can communicate availability without leaking details.