Added missing environment variables

gitea/.env.sample

@@ -8,3 +8,14 @@
 #GITEA_TAG=latest
 #GITEA_PORT_HTTP=3000
 #GITEA_PORT_SSH=22
+#GITEA__openid__ENABLE_OPENID_SIGNIN=false
+#GITEA__openid__ENABLE_OPENID_SIGNUP=false
+#GITEA__service__DISABLE_REGISTRATION=false
+#GITEA_MARIADB_PORT=3306
+#GITEA_MARIADB_DATABASE=gitea
+#GITEA_MARIADB_USER=gitea
+#GITEA_MARIADB_PASSWORD=gitea
+#GITEA_MARIADB_ROOT_PASSWORD=gitea
+#GITEA_POSTGRESQL_DATABASE=gitea
+#GITEA_POSTGRESQL_USER=gitea
+#GITEA_POSTGRESQL_PASSWORD=gitea