add Jenkinsfile.nix.linux for building /nix/store

Signed-off-by: Jakub Sokołowski <jakub@status.im>

ci/Jenkinsfile.nix.linux

@@ -0,0 +1,42 @@
+pipeline {
+  agent {
+    docker {
+      label 'linux'
+      image 'nixos/nix'
+      args '-u 0:0'
+    }
+  }
+
+  environment {
+    NIX_CACHE_HOST = 'nix-cache@master-01.do-ams3.ci.misc.statusim.net'
+  }
+
+  options {
+    timestamps()
+    /* Prevent Jenkins jobs from running forever */
+    timeout(time: 50, unit: 'MINUTES')
+    /* Limit builds retained */
+    buildDiscarder(logRotator(
+      numToKeepStr: '20',
+      daysToKeepStr: '30',
+    ))
+  }
+
+  stages {
+    stage('Build') {
+      steps {
+        sh 'nix-build -A env'
+      }
+    }
+    stage('Upload') {
+      steps {
+        sshagent(credentials: ['nix-cache-ssh']) {
+          sh """
+            rsync -e 'ssh -o StrictHostKeyChecking=no' -r \
+              /nix/store/. ${env.NIX_CACHE_HOST}:/nix/store/
+          """
+        }
+      }
+    }
+  }
+}