Change semester type in db

config/db_schema_postgres.sql

@@ -48,7 +48,7 @@ CREATE TABLE IF NOT EXISTS "courses_data" (
     "created_by" integer DEFAULT NULL,
     "time_created" timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, -- TODO info: default was not present
     "time_updated" timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, -- TODO info: default was not present
-    "semester" char(6) NOT NULL DEFAULT '',
+    "semester" character varying(6) NOT NULL DEFAULT '',
     "settings" text COLLATE "pg_catalog"."und-x-icu" NOT NULL DEFAULT '',
     "downloadable" boolean NOT NULL DEFAULT true,
     "embedinvisible" boolean NOT NULL DEFAULT false,