add support for smallint type on migration (#144)

Author: ahsanulks

column.go

@@ -8,6 +8,8 @@ const (
 	ID ColumnType = "ID"
 	// Bool ColumnType.
 	Bool ColumnType = "BOOL"
+	// SmallInt ColumnType.
+	SmallInt ColumnType = "SMALLINT"
 	// Int ColumnType.
 	Int ColumnType = "INT"
 	// BigInt ColumnType.

table.go

@@ -31,6 +31,11 @@ func (t *Table) Bool(name string, options ...ColumnOption) {
 	t.Column(name, Bool, options...)
 }
 
+// SmallInt defines a column with name and Small type.
+func (t *Table) SmallInt(name string, options ...ColumnOption) {
+	t.Column(name, SmallInt, options...)
+}
+
 // Int defines a column with name and Int type.
 func (t *Table) Int(name string, options ...ColumnOption) {
 	t.Column(name, Int, options...)

table_test.go

@@ -25,6 +25,14 @@ func TestTable(t *testing.T) {
 		}, table.Definitions[len(table.Definitions)-1])
 	})
 
+	t.Run("SmallInt", func(t *testing.T) {
+		table.SmallInt("smallint")
+		assert.Equal(t, Column{
+			Name: "smallint",
+			Type: SmallInt,
+		}, table.Definitions[len(table.Definitions)-1])
+	})
+
 	t.Run("Int", func(t *testing.T) {
 		table.Int("integer")
 		assert.Equal(t, Column{