Update readme

README.md

@@ -23,17 +23,26 @@ Utilizing the native PostgreSQL COPY command, pg-subsetter performs data transfe
 ```
 Usage of subsetter:
   -dst string
-        Destination DSN
+        Destination database DSN
   -f float
         Fraction of rows to copy (default 0.05)
+  -force value
+        Query to copy required tables (users: id = 1)
   -src string
-        Source DSN
+        Source database DSN
 ```
 
 
-Example:
+### Example
 
-```pg-subsetter -src postgresql://:@/bigdb -dst postgresql://:@/littledb -f 0.05```
+```
+pg-subsetter 
+      -src postgresql://:@/bigdb 
+      -dst postgresql://:@/littledb 
+      -f 0.05 
+      -force "users: id = 1" 
+      -force "groups: id = 12"
+```
 
 # Installing
 

cli/force.go

@@ -0,0 +1,14 @@
+package main
+
+import "strings"
+
+type arrayForce []string
+
+func (i *arrayForce) String() string {
+	return "users:id=1"
+}
+
+func (i *arrayForce) Set(value string) error {
+	*i = append(*i, strings.TrimSpace(value))
+	return nil
+}

cli/main.go

@@ -9,10 +9,11 @@ import (
 var src = flag.String("src", "", "Source database DSN")
 var dst = flag.String("dst", "", "Destination database DSN")
 var fraction = flag.Float64("f", 0.05, "Fraction of rows to copy")
+var forceSync arrayForce
 
 func main() {
+	flag.Var(&forceSync, "force", "Query to copy required tables (users: id = 1)")
 	flag.Parse()
-	log.Info().Msg("Starting")
 
 	if *src == "" || *dst == "" {
 		log.Fatal().Msg("Source and destination DSNs are required")

flake.nix

@@ -37,7 +37,6 @@
               golangci-lint
               postgresql
               process-compose
-              shellcheck
               nixpkgs-fmt
               pgweb
             ];