diff --git a/yarn.lock b/yarn.lock
index 05ba9e9..1c2cb64 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -37,7 +37,7 @@
     "@platzi/markdown" "1.0.1"
     prop-types "^15.5.4"
 
-abab@^1.0.3:
+abab@1.0.3:
   version "1.0.3"
   resolved "https://registry.yarnpkg.com/abab/-/abab-1.0.3.tgz#b81de5f7274ec4e756d797cd834f303642724e5d"
 
@@ -1462,7 +1462,7 @@ expand-range@^1.8.1:
   dependencies:
     fill-range "^2.1.0"
 
-express@^4.15.2:
+express@4.15.2:
   version "4.15.2"
   resolved "https://registry.yarnpkg.com/express/-/express-4.15.2.tgz#af107fc148504457f2dca9a6f2571d7129b97b35"
   dependencies:
@@ -1644,7 +1644,7 @@ fstream-ignore@^1.0.5:
     inherits "2"
     minimatch "^3.0.0"
 
-fstream@^1.0.0, fstream@^1.0.10, fstream@^1.0.2:
+fstream@^1.0.0, fstream@^1.0.10:
   version "1.0.11"
   resolved "https://registry.yarnpkg.com/fstream/-/fstream-1.0.11.tgz#5c1fb1f117477114f0632a0eb4b71b3cb0fd3171"
   dependencies:
@@ -1653,6 +1653,15 @@ fstream@^1.0.0, fstream@^1.0.10, fstream@^1.0.2:
     mkdirp ">=0.5 0"
     rimraf "2"
 
+fstream@^1.0.12:
+  version "1.0.12"
+  resolved "https://registry.yarnpkg.com/fstream/-/fstream-1.0.12.tgz#4e8ba8ee2d48be4f7d0de505455548eae5932045"
+  dependencies:
+    graceful-fs "^4.1.2"
+    inherits "~2.0.0"
+    mkdirp ">=0.5 0"
+    rimraf "2"
+
 function-bind@^1.0.2, function-bind@^1.1.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/function-bind/-/function-bind-1.1.0.tgz#16176714c801798e4e8f2cf7f7529467bb4a5771"
@@ -1880,7 +1889,7 @@ ignore-by-default@^1.0.0:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/ignore-by-default/-/ignore-by-default-1.0.1.tgz#48ca6d72f6c6a3af00a9ad4ae6876be3889e2b09"
 
-immutable@^3.8.1:
+immutable@3.8.1:
   version "3.8.1"
   resolved "https://registry.yarnpkg.com/immutable/-/immutable-3.8.1.tgz#200807f11ab0f72710ea485542de088075f68cd2"
 
@@ -2079,7 +2088,7 @@ isobject@^2.0.0:
   dependencies:
     isarray "1.0.0"
 
-isomorphic-fetch@^2.1.1, isomorphic-fetch@^2.2.1:
+isomorphic-fetch@2.2.1, isomorphic-fetch@^2.1.1:
   version "2.2.1"
   resolved "https://registry.yarnpkg.com/isomorphic-fetch/-/isomorphic-fetch-2.2.1.tgz#611ae1acf14f5e81f729507472819fe9733558a9"
   dependencies:
@@ -2297,7 +2306,7 @@ lowercase-keys@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/lowercase-keys/-/lowercase-keys-1.0.0.tgz#4e3366b39e7f5457e35f1324bdf6f88d0bfc7306"
 
-lru-cache@^4.0.1, lru-cache@^4.0.2:
+lru-cache@4.0.2, lru-cache@^4.0.1:
   version "4.0.2"
   resolved "https://registry.yarnpkg.com/lru-cache/-/lru-cache-4.0.2.tgz#1d17679c069cda5d040991a09dbc2c0db377e55e"
   dependencies:
@@ -2619,7 +2628,7 @@ node-pre-gyp@^0.6.29:
     tar "^2.2.1"
     tar-pack "^3.4.0"
 
-nodemon@^1.11.0:
+nodemon@1.11.0:
   version "1.11.0"
   resolved "https://registry.yarnpkg.com/nodemon/-/nodemon-1.11.0.tgz#226c562bd2a7b13d3d7518b49ad4828a3623d06c"
   dependencies:
@@ -3013,7 +3022,7 @@ react-deep-force-update@^2.0.1:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/react-deep-force-update/-/react-deep-force-update-2.0.1.tgz#4f7f6c12c3e7de42f345992a3c518236fa1ecad3"
 
-react-dom@^15.5.4:
+react-dom@15.5.4:
   version "15.5.4"
   resolved "https://registry.yarnpkg.com/react-dom/-/react-dom-15.5.4.tgz#ba0c28786fd52ed7e4f2135fe0288d462aef93da"
   dependencies:
@@ -3039,7 +3048,7 @@ react-proxy@^3.0.0-alpha.0:
   dependencies:
     lodash "^4.6.1"
 
-react@^15.5.4:
+react@15.5.4:
   version "15.5.4"
   resolved "https://registry.yarnpkg.com/react/-/react-15.5.4.tgz#fa83eb01506ab237cdc1c8c3b1cea8de012bf047"
   dependencies:
@@ -3518,11 +3527,11 @@ tar-pack@^3.4.0:
     uid-number "^0.0.6"
 
 tar@^2.2.1:
-  version "2.2.1"
-  resolved "https://registry.yarnpkg.com/tar/-/tar-2.2.1.tgz#8e4d2a256c0e2185c6b18ad694aec968b83cb1d1"
+  version "2.2.2"
+  resolved "https://registry.yarnpkg.com/tar/-/tar-2.2.2.tgz#0ca8848562c7299b8b446ff6a4d60cdbb23edc40"
   dependencies:
     block-stream "*"
-    fstream "^1.0.2"
+    fstream "^1.0.12"
     inherits "2"
 
 thenify-all@^1.0.0: