Add data layer

This includes config changes, collections, posts, some post rendering
funcs, and actual database connection when the server starts up.

errors.go

@@ -7,5 +7,24 @@ import (
 
 // Commonly returned HTTP errors
 var (
-	ErrInternalCookieSession = impart.HTTPError{http.StatusInternalServerError, "Could not get cookie session."}
+	ErrBadAccessToken = impart.HTTPError{http.StatusUnauthorized, "Invalid access token."}
+	ErrNoAccessToken  = impart.HTTPError{http.StatusBadRequest, "Authorization token required."}
+
+	ErrForbiddenCollection  = impart.HTTPError{http.StatusForbidden, "You don't have permission to add to this collection."}
+	ErrUnauthorizedEditPost = impart.HTTPError{http.StatusUnauthorized, "Invalid editing credentials."}
+	ErrUnauthorizedGeneral  = impart.HTTPError{http.StatusUnauthorized, "You don't have permission to do that."}
+
+	ErrInternalGeneral = impart.HTTPError{http.StatusInternalServerError, "The humans messed something up. They've been notified."}
+
+	ErrCollectionPageNotFound = impart.HTTPError{http.StatusNotFound, "Collection page doesn't exist."}
+	ErrPostNotFound           = impart.HTTPError{Status: http.StatusNotFound, Message: "Post not found."}
+	ErrPostUnpublished        = impart.HTTPError{Status: http.StatusGone, Message: "Post unpublished by author."}
+	ErrPostFetchError         = impart.HTTPError{Status: http.StatusInternalServerError, Message: "We encountered an error getting the post. The humans have been alerted."}
+
+	ErrUserNotFound = impart.HTTPError{http.StatusNotFound, "User doesn't exist."}
+)
+
+// Post operation errors
+var (
+	ErrPostNoUpdatableVals = impart.HTTPError{http.StatusBadRequest, "Supply some properties to update."}
 )