add --db-file-lt if db-file is enabled

fixes: #98

README.md

@@ -527,7 +527,8 @@ Note - due to design limitations of `readsb`, the `tar1090` graphical interface
 | `GZIP_LVL`                 | `1`-`9` are valid, lower lvl: less CPU usage, higher level: less network bandwidth used when loading the page                                                                                      | `3`                  |
 | `PTRACKS`                  | Shows the last `$PTRACKS` hours of traces you have seen at the `?pTracks` URL                                                                                                                      | `8`                  |
 | `TAR1090_FLIGHTAWARELINKS` | Set to `true` to enable FlightAware links in the web interface                                                                                                                                     | `null`               |
-| `TAR1090_ENABLE_AC_DB`     | Set to `true` to enable extra information, such as aircraft type and registration, to be included in in `aircraft.json` output. Will use more memory; use caution on older Pis or similar devices. | `false`              |
+| `TAR1090_ENABLE_AC_DB`     | Set to `true` to enable extra information, such as aircraft type and registration, to be included in in `aircraft.json` output. Will use more 50 MB extra memory                                   | `false`              |
+| `TAR1090_DB_LONGTYPE`      | Set to `false` to remove the "desc", "ownOp" and "year" fields from `aircraft.json` when AC_DB is enabled.                                                                                         | `true`              |
 | `HEYWHATSTHAT_PANORAMA_ID` | Your `heywhatsthat.com` panorama ID. See <https://github.com/wiedehopf/tar1090#heywhatsthatcom-range-outline> (will reveal exact location in the webinterface)                                     |                      |
 | `HEYWHATSTHAT_ALTS`        | Comma separated altitudes for multiple outlines. Use no units or `ft` for feet, `m` for meters, or `km` for kilometers. Only integer numbers are accepted, no decimals please                      | `12192m` (=40000 ft) |
 | `HTTP_ACCESS_LOG`          | Optional. Set to `true` to display HTTP server access logs.                                                                                                                                        | `false`              |

rootfs/etc/s6-overlay/scripts/readsb

@@ -283,6 +283,9 @@ if chk_enabled "$TAR1090_ENABLE_AC_DB"; then
         # fallback to container supplied not updated csv.gz
         READSB_CMD+=("--db-file=$TAR1090_INSTALL_DIR/aircraft.csv.gz")
     fi
+    if ! chk_disabled "$TAR1090_DB_LONGTYPE"; then
+        READSB_CMD+=("--db-file-lt")
+    fi
 fi
 
 # Handle "--device-type"