diff --git a/go.mod b/go.mod
index 62d4bb6..e8d5db1 100644
--- a/go.mod
+++ b/go.mod
@@ -5,12 +5,11 @@
 	github.com/gomodule/redigo v2.0.0+incompatible
 	github.com/googleapis/gax-go v2.0.0+incompatible // indirect
 	go.opencensus.io v0.19.0 // indirect
-	golang.org/x/crypto v0.0.0-20181025213731-e84da0312774
-	golang.org/x/net v0.0.0-20190213061140-3a22650c66bd
+	golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2
+	golang.org/x/net v0.0.0-20190311183353-d8887717615a
 	golang.org/x/oauth2 v0.0.0-20190115181402-5dab4167f31c // indirect
-	golang.org/x/sys v0.0.0-20190209173611-3b5209105503 // indirect
 	golang.org/x/text v0.3.1-0.20181227161524-e6919f6577db // indirect
-	golang.org/x/tools v0.0.0-20190307163923-6a08e3108db3
+	golang.org/x/tools v0.0.0-20190516015132-d1a3278ee749
 	google.golang.org/api v0.1.0 // indirect
 	google.golang.org/appengine v1.4.0
 	google.golang.org/genproto v0.0.0-20190123001331-8819c946db44 // indirect
diff --git a/go.sum b/go.sum
index f5ca2a3..c88f4a6 100644
--- a/go.sum
+++ b/go.sum
@@ -37,8 +37,8 @@
 go.opencensus.io v0.18.0/go.mod h1:vKdFvxhtzZ9onBp9VKHK8z/sRpBMnKAsufL7wlDrCOA=
 go.opencensus.io v0.19.0 h1:+jrnNy8MR4GZXvwF9PEuSyHxA4NaTf6601oNRwCSXq0=
 go.opencensus.io v0.19.0/go.mod h1:AYeH0+ZxYyghG8diqaaIq/9P3VgCCt5GF2ldCY4dkFg=
-golang.org/x/crypto v0.0.0-20181025213731-e84da0312774 h1:a4tQYYYuK9QdeO/+kEvNYyuR21S+7ve5EANok6hABhI=
-golang.org/x/crypto v0.0.0-20181025213731-e84da0312774/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2 h1:VklqNMn3ovrHsnt90PveolxSbWFaJdECFbxSq0Mqo2M=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/lint v0.0.0-20180702182130-06c8688daad7/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
@@ -51,8 +51,8 @@
 golang.org/x/net v0.0.0-20181201002055-351d144fa1fc/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20181217023233-e147a9138326/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190108225652-1e06a53dbb7e/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
-golang.org/x/net v0.0.0-20190213061140-3a22650c66bd h1:HuTn7WObtcDo9uEEU7rEqL0jYthdXAmZ6PP+meazmaU=
-golang.org/x/net v0.0.0-20190213061140-3a22650c66bd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20190311183353-d8887717615a h1:oWX7TPOiFAMXLq8o0ikBYfCJVlRHBcsciT5bXOrH628=
+golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20181203162652-d668ce993890 h1:uESlIz09WIHT2I+pasSXcpLYqYK8wHcdCetU3VuMBJE=
 golang.org/x/oauth2 v0.0.0-20181203162652-d668ce993890/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
@@ -62,19 +62,21 @@
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4 h1:YUO/7uOKsKeq9UokNS62b8FYywz3ker1l1vDZRCRefw=
 golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58 h1:8gQV6CLnAEikrhgkHFbMAEhagSSnXWGV915qUMm9mrU=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20181218192612-074acd46bca6/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20190209173611-3b5209105503 h1:5SvYFrOM3W8Mexn9/oA44Ji7vhXAZQ9hiP+1Q/DMrWg=
-golang.org/x/sys v0.0.0-20190209173611-3b5209105503/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a h1:1BGLXjeY4akVXGgbC9HugT3Jv3hCI0z56oJR5vAMgBU=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.1-0.20181227161524-e6919f6577db h1:6/JqlYfC1CCaLnGceQTI+sDGhC9UBSPAsBqI0Gun6kU=
 golang.org/x/text v0.3.1-0.20181227161524-e6919f6577db/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/tools v0.0.0-20180828015842-6cd1fcedba52/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20181219222714-6e267b5cc78e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/tools v0.0.0-20190307163923-6a08e3108db3 h1:2oZsfYnKfYzL4I57uYiRFsUf0bqlLkiuw8nnj3+voUA=
-golang.org/x/tools v0.0.0-20190307163923-6a08e3108db3/go.mod h1:25r3+/G6/xytQM8iWZKq3Hn0kr0rgFKPUNVEL/dr3z4=
+golang.org/x/tools v0.0.0-20190516015132-d1a3278ee749 h1:L1RW4r06KGFktOvNizsWNBWHn4V2I/p9SNRLhNn6hzM=
+golang.org/x/tools v0.0.0-20190516015132-d1a3278ee749/go.mod h1:RgjU9mgBXZiqYHBnxXauZ1Gv1EHHAz9KjViQ78xBX0Q=
 google.golang.org/api v0.0.0-20180910000450-7ca32eb868bf/go.mod h1:4mhQ8q/RsB7i+udVvVy5NUi08OU8ZlA0gRVgrF7VFY0=
 google.golang.org/api v0.0.0-20181220000619-583d854617af/go.mod h1:4mhQ8q/RsB7i+udVvVy5NUi08OU8ZlA0gRVgrF7VFY0=
 google.golang.org/api v0.1.0 h1:K6z2u68e86TPdSdefXdzvXgR1zEMa+459vBSfWYAZkI=