diff --git a/Gopkg.lock b/Gopkg.lock
index 869a7ac9..d6f850df 100644
--- a/Gopkg.lock
+++ b/Gopkg.lock
@@ -58,12 +58,11 @@
   revision = "9fd32a8b3d3d3f9d43c341bfe098430e07609480"
 
 [[projects]]
-  digest = "1:a3b08eb3ec49caec29db596d8f2aae79614413a8d2068d5082b92fa23b5b6d80"
+  digest = "1:8abef4b9ca2f94e008688685bf8fb7bb27e5c82b353a82ef9276a27b4a6d2020"
   name = "github.com/carlosms/asciigraph"
   packages = ["."]
   pruneopts = "NUT"
-  revision = "b8c6bd8cace5d89062a57acb2012b0be08fb9525"
-  version = "v0.4.1"
+  revision = "22e3e1b9e3cd5ab4f79619cd65987f426d2d3dc4"
 
 [[projects]]
   branch = "master"
diff --git a/Gopkg.toml b/Gopkg.toml
index 412e63c3..c7ba9ed6 100644
--- a/Gopkg.toml
+++ b/Gopkg.toml
@@ -41,6 +41,6 @@
   branch = "master"
   name = "github.com/spkg/bom"
 
-# [[constraint]]
-#   name = "github.com/docker/docker"
-#   version = "v17"
+[[constraint]]
+  name = "github.com/carlosms/asciigraph"
+  revision = "22e3e1b9e3cd5ab4f79619cd65987f426d2d3dc4"
diff --git a/vendor/github.com/carlosms/asciigraph/asciigraph.go b/vendor/github.com/carlosms/asciigraph/asciigraph.go
index 63defb69..3dde5d36 100644
--- a/vendor/github.com/carlosms/asciigraph/asciigraph.go
+++ b/vendor/github.com/carlosms/asciigraph/asciigraph.go
@@ -9,6 +9,7 @@ import (
 
 // Plot returns ascii graph for a series.
 func Plot(series []float64, options ...Option) string {
+	var logMaximum float64
 	config := configure(config{
 		Offset: 3,
 	}, options)
@@ -18,6 +19,13 @@ func Plot(series []float64, options ...Option) string {
 	}
 
 	minimum, maximum := minMaxFloat64Slice(series)
+	if config.Min != nil && *config.Min < minimum {
+		minimum = *config.Min
+	}
+	if config.Max != nil && *config.Max > maximum {
+		maximum = *config.Max
+	}
+
 	interval := math.Abs(maximum - minimum)
 
 	if config.Height <= 0 {
@@ -32,7 +40,12 @@ func Plot(series []float64, options ...Option) string {
 		config.Offset = 3
 	}
 
-	ratio := float64(config.Height) / interval
+	var ratio float64
+	if interval != 0 {
+		ratio = float64(config.Height) / interval
+	} else {
+		ratio = 1
+	}
 	min2 := round(minimum * ratio)
 	max2 := round(maximum * ratio)
 
@@ -54,7 +67,10 @@ func Plot(series []float64, options ...Option) string {
 	}
 
 	precision := 2
-	logMaximum := math.Log10(math.Max(math.Abs(maximum), math.Abs(minimum))) //to find number of zeros after decimal
+	logMaximum = math.Log10(math.Max(math.Abs(maximum), math.Abs(minimum))) //to find number of zeros after decimal
+	if minimum == float64(0) && maximum == float64(0) {
+		logMaximum = float64(-1)
+	}
 
 	if logMaximum < 0 {
 		// negative log
@@ -74,7 +90,14 @@ func Plot(series []float64, options ...Option) string {
 
 	// axis and labels
 	for y := intmin2; y < intmax2+1; y++ {
-		label := fmt.Sprintf("%*.*f", maxWidth+1, precision, maximum-(float64(y-intmin2)*interval/float64(rows)))
+		var magnitude float64
+		if rows > 0 {
+			magnitude = maximum - (float64(y-intmin2) * interval / float64(rows))
+		} else {
+			magnitude = float64(y)
+		}
+
+		label := fmt.Sprintf("%*.*f", maxWidth+1, precision, magnitude)
 		w := y - intmin2
 		h := int(math.Max(float64(config.Offset)-float64(len(label)), 0))
 
@@ -99,12 +122,9 @@ func Plot(series []float64, options ...Option) string {
 		} else {
 			if y0 > y1 {
 				plot[rows-y1][x+config.Offset] = "╰"
-			} else {
-				plot[rows-y1][x+config.Offset] = "╭"
-			}
-			if y0 > y1 {
 				plot[rows-y0][x+config.Offset] = "╮"
 			} else {
+				plot[rows-y1][x+config.Offset] = "╭"
 				plot[rows-y0][x+config.Offset] = "╯"
 			}
 
diff --git a/vendor/github.com/carlosms/asciigraph/options.go b/vendor/github.com/carlosms/asciigraph/options.go
index 7ecf3794..04a42e4a 100644
--- a/vendor/github.com/carlosms/asciigraph/options.go
+++ b/vendor/github.com/carlosms/asciigraph/options.go
@@ -12,6 +12,7 @@ type Option interface {
 // config holds various graph options
 type config struct {
 	Width, Height int
+	Min, Max      *float64
 	Offset        int
 	Caption       string
 }
@@ -54,6 +55,18 @@ func Height(h int) Option {
 	})
 }
 
+// Min sets the graph's minimum value for the vertical axis. It will be ignored
+// if the series contains a lower value.
+func Min(min float64) Option {
+	return optionFunc(func(c *config) { c.Min = &min })
+}
+
+// Max sets the graph's maximum value for the vertical axis. It will be ignored
+// if the series contains a bigger value.
+func Max(max float64) Option {
+	return optionFunc(func(c *config) { c.Max = &max })
+}
+
 // Offset sets the graphs offset.
 func Offset(o int) Option {
 	return optionFunc(func(c *config) { c.Offset = o })