Add migrations to remove features table

Author: dpordomingo

cli/migrations/README.md

@@ -27,3 +27,9 @@ go run cli/migrations/*.go uast-import internal.db source.db
 # prepares the current "internal.db". Remove "diff" col
 go run cli/migrations/*.go diff-rm-col internal.db
 ```
+
+- [Remove features table from a database](command-features-drop-table.go)
+```shell
+# drops the 'features' table from the current "internal.db"
+go run cli/migrations/*.go features-drop-table internal.db
+```

cli/migrations/command-features-drop-table.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/src-d/code-annotation/server/dbutil"
+)
+
+type featureDropCmd struct {
+	commandDesc
+	Args struct {
+		InternalDBPath string `description:"filepath to the internal SQLite database"`
+	} `positional-args:"yes" required:"yes"`
+}
+
+var featureDropOpts = featureDropCmd{
+	commandDesc: commandDesc{
+		name:      "features-drop-table",
+		shortDesc: "Drop Features table",
+		longDesc:  "Removes the Features table from the sqlite://InternalDBPath database",
+	},
+}
+
+// queries
+const (
+	dropFeaturesTableQuery = "DROP TABLE features"
+)
+
+func (c *featureDropCmd) Execute(args []string) error {
+	internalDb, err := dbutil.Open(fmt.Sprintf(sqliteDSN, c.Args.InternalDBPath), false)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	defer internalDb.Close()
+
+	if err := dropFeaturesTable(internalDb); err != nil {
+		log.Fatal(err)
+	}
+
+	log.Println("Features table was deleted")
+	return nil
+}
+
+func dropFeaturesTable(db dbutil.DB) error {
+	if _, err := db.Exec(dropFeaturesTableQuery); err != nil {
+		return err
+	}
+
+	return nil
+}

cli/migrations/main.go

@@ -18,6 +18,7 @@ func main() {
 	addCommand(parser, &uastColsOpts)
 	addCommand(parser, &uastImportOpts)
 	addCommand(parser, &diffRmColOpts)
+	addCommand(parser, &featureDropOpts)
 	addCommand(parser, &vacuumOpts)
 	parse(parser, description)
 }